Culture device and method for controlling culture device

Abstract

A culture device for culturing microorganisms or cells in which a starting material gas including a combustible gas is used for proliferation or generation of an organic substance, the culture device being provided with: a culture tank for accommodating a culture solution; a raw material gas supply unit for supplying a raw material gas to the culture tank; and a composition ratio control means for measuring the composition ratio of the mixed gas in a space above the liquid level of the culture solution in the culture tank, and supplying a gas for adjustment into the space on the basis of the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a preset explosion range. When the equivalent circle diameter of a cross section orthogonal to the height direction of the culture tank is DAm and the maximum height of the liquid surface is H, the size of the culture tank satisfies the condition H / DAm > = 2.

Description

Technical Field

[0001] The present invention relates to a culture device and a method for controlling the culture device. Background Technology

[0002] Research into the depetrochemicalization of raw materials is gaining momentum globally, aiming to curb greenhouse gas emissions. As part of this research, technologies utilizing carbon sources other than petroleum as raw materials have been developed in the manufacturing of chemical and biological products. For example, microorganisms that utilize carbon sources other than petroleum as raw materials for proliferation or the production of organic matter are known. One example of such microorganisms is hydroxide bacteria. Hydroxyhydric bacteria proliferate by ingesting gases containing carbon dioxide, hydrogen, and oxygen as raw materials, and then efficiently produce organic substances such as alcohols and amino acids by altering their genes. Hydroxyhydric bacteria are a general term for chemically synthesizing bacteria that utilize energy generated through the oxidation of hydrogen to convert carbon contained in carbon dioxide into organic matter and ingest it. In hydroxide bacteria, carbon dioxide is the raw material for proliferation or the production of organic matter; therefore, the efficient utilization of carbon dioxide emitted as a greenhouse gas has attracted considerable attention.

[0003] Japanese Patent Publication No. 2564008 and U.S. Patent Application Publication No. 2019 / 0316072 disclose a culture apparatus for cultivating hydroxide bacteria. The apparatus includes a culture tank containing a culture medium. A raw material gas containing carbon dioxide, hydrogen, and oxygen is supplied to the culture tank. A portion of the carbon dioxide, hydrogen, and oxygen in the raw material gas dissolves in the culture medium and is consumed in the proliferation of hydroxide bacteria or the production of organic matter. The remaining raw material gas is released into the space above the surface of the culture medium within the culture tank and discharged outside the tank. Since a mixture of hydrogen and oxygen, which are flammable gases, poses an explosion hazard depending on its composition ratio, Japanese Patent Publication No. 2564008 and U.S. Patent Application Publication No. 2019 / 0316072 disclose a technique for suppressing explosions.

[0004] In Japanese Patent Publication No. 2564008, the dissolved oxygen concentration in the culture medium is measured, and the amount of oxygen supplied to the culture tank is limited based on the measured dissolved oxygen concentration, enabling independent control of the oxygen supply in the feed gas. In U.S. Patent Application Publication No. 2019 / 0316072, safety is ensured by controlling the composition of the feed gas.

[0005] Furthermore, International Publication No. 2011 / 070791 discloses a cultivation apparatus for culturing microorganisms, etc. International Publication No. 2011 / 070791 describes a technique for improving oxygen utilization efficiency by reducing the diameter of gas bubbles in the raw material gas. Japanese Patent Application Publication No. 2013-005754 and International Publication No. 2006 / 101074 describe a technique for improving the solubility of the raw material gas by using a longitudinally elongated cultivation tank. International Publication No. 2016 / 117023, although not using a flammable gas as the raw material gas, describes a technique for suppressing damage to microorganisms, i.e., bacterial cells, within the cultivation tank. Summary of the Invention The technical problem to be solved by the invention

[0006] In the case of feed gas containing flammable gases, the mixed gas released from the culture medium in the culture tank poses an explosion hazard, therefore, explosion suppression technology is very important. In the methods described in Japanese Patent No. 2564008 and the like, there is room for improvement in the safety measures regarding explosion suppression.

[0007] The present invention provides a culture device and a control method for the culture device that improve safety compared to the past when culturing microorganisms or cells that use a raw material gas containing flammable gas for proliferation or the production of organic matter. means for solving technical problems

[0008] To achieve the above objectives, the first culture apparatus according to the present invention is a culture apparatus for culturing microorganisms or cells that use a raw material gas containing flammable gas for proliferation or the production of organic matter. This culture apparatus includes: a culture tank containing a culture medium for culturing microorganisms or cells; a raw material gas supply unit for supplying raw material gas to the culture tank; a composition ratio control mechanism for measuring the composition ratio of a mixed gas in a space above the surface of the culture medium within the culture tank, and supplying an adjustment gas to the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a predetermined explosion range; a gas circulation path for reusing the mixed gas in the space as a raw material gas; and a solubility control mechanism for measuring, during culture, the proportion of flammable gas dissolved in the culture medium from the flammable gas contained in the raw material gas supplied to the culture tank through the gas circulation path or the raw material gas supply unit, i.e., the flammable gas solubility rate, and maintaining the measured flammable gas solubility rate above a predetermined target value.

[0009] The control method of the first culture device involved in the present invention is a control method for a culture device having a culture tank and a raw material gas supply unit for culturing microorganisms or cells. The culture tank contains a culture solution, and the culture solution is used to cultivate microorganisms or cells that use a raw material gas containing flammable gas for proliferation or the production of organic matter. The raw material gas supply unit supplies a raw material gas containing flammable gas to the culture tank. In the control method of the culture device, the composition ratio of the mixed gas in the space above the liquid surface of the culture solution in the culture tank is measured, and an adjustment gas is supplied to the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a predetermined explosion range. During cultivation, the proportion of flammable gas dissolved in the culture solution in the raw material gas supplied to the culture tank by the raw material gas supply unit through a gas circulation path for reusing the mixed gas in the space as a raw material gas, i.e., the flammable gas solubility rate, is measured, and the measured flammable gas solubility rate is maintained at a predetermined target value.

[0010] The second culture apparatus involved in the present invention is a culture apparatus for culturing microorganisms or cells that use a raw material gas containing flammable gas for proliferation or the production of organic matter. The culture apparatus includes: a culture tank containing a culture medium for culturing microorganisms or cells; a raw material gas supply unit for supplying raw material gas to the culture tank; and a composition ratio control mechanism for measuring the composition ratio of a mixed gas in the space above the liquid surface of the culture medium in the culture tank, and supplying an adjustment gas into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a predetermined explosion range. When the equivalent circle diameter of the cross section orthogonal to the height direction of the culture tank is set as DAm, and the maximum height of the liquid surface is set as H, the size of the culture tank satisfies the condition H / DAm≥2.

[0011] The control method of the second culture device involved in the present invention is a control method for a culture device having a culture tank and a raw material gas supply unit for culturing microorganisms or cells. The culture tank contains a culture solution, which is used to cultivate microorganisms or cells that use a raw material gas containing a combustible gas for proliferation or the production of organic matter. The raw material gas supply unit supplies a raw material gas containing a combustible gas to the culture tank. In the control method of the culture device, when the equivalent circle diameter of the cross section orthogonal to the height direction of the culture tank is set as DAm and the maximum height of the liquid surface is set as H, the size of the culture tank satisfies the condition H / DAm≥2. The composition ratio of the mixed gas in the space above the liquid surface of the culture solution in the culture tank is measured, and an adjustment gas is supplied to the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a predetermined explosion range.

[0012] The third culture apparatus involved in the present invention is a culture apparatus for culturing microorganisms or cells that use a raw material gas containing combustible gas for proliferation or the production of organic matter. The culture apparatus comprises: a culture tank for containing a culture medium for culturing microorganisms or cells; a culture medium tank for storing the culture medium supplied to the culture tank; a culture target supply channel for supplying microorganisms or cells to the culture tank; a raw material gas tank for storing raw material gas; a bubble generating device for mixing the raw material gas with the culture medium before it is supplied to the culture tank; and a culture medium supply channel disposed between the culture medium tank and the culture tank for supplying the culture medium after the raw material gas is mixed by the bubble generating device to the culture tank, and is disposed separately from the culture target supply channel.

[0013] The fourth culture apparatus according to the present invention is a culture apparatus for culturing microorganisms or cells that use a raw material gas containing combustible gas for proliferation or the production of organic matter. The culture apparatus includes: a culture tank containing a culture medium for culturing microorganisms or cells; a raw material gas supply unit for supplying raw material gas to the culture tank; a gas circulation path for reusing the mixed gas existing in the space above the liquid surface of the culture medium in the culture tank as a raw material gas; and a pressure imposing device disposed on the gas circulation path for imposing a circulation pressure on the mixed gas to circulate the mixed gas. The pressure imposing device does not have a mechanically movable part and uses a drive fluid input from the outside to the pressure imposing device to impose the circulation pressure on the mixed gas. Invention Effects

[0014] According to the technology of the present invention, when culturing microorganisms or cells that use a raw material gas containing flammable gas for proliferation or the production of organic matter, safety can be improved compared to the past. Attached Figure Description

[0015] Figure 1 This is a diagram illustrating the function of the culture apparatus. Figure 2 This is a diagram showing the overall structure of the culture device. Figure 3 This is a diagram showing the structure of supplying raw material gases according to their composition. Figure 4 This is a diagram illustrating the structure for recovering and reusing culture medium. Figure 5 It is a diagram showing the structure of a specific component isolated from the culture medium. Figure 6 This is a diagram showing the configuration of the culture medium outlet. Figure 7 This is a graph representing the index of bubble diameter. Figure 8 This is a diagram representing surface tension reducing agents. Figure 9This is a diagram showing the structure for reusing waste gas. Figure 10 It is a diagram showing the structure used for various controls. Figure 11 It is a diagram showing the structure controlled by the composition ratio of the mixed gas. Figure 12 This is a diagram showing the structure for controlling solubility and consumption. Figure 13 This is a flowchart of the process for controlling the composition ratio of the mixed gas. Figure 14 This is a flowchart of the hydrogen solubility control process. Figure 15 This is a flowchart of the hydrogen consumption rate control process. Figure 16 This is a diagram illustrating the effects of the first embodiment. Figure 17 This is a diagram showing the culture tank of the second embodiment. Figure 18 This is a diagram showing a first modified example of the culture tank of the second embodiment. Figure 19 This is a diagram showing a second variation of the culture tank according to the second embodiment. Figure 20 This is a diagram showing a third variation of the culture tank in the second embodiment. Figure 21 This is a diagram showing a fourth variation of the culture tank in the second embodiment. Figure 22 This is a diagram showing the culture apparatus of the third embodiment. Figure 23 This is a diagram showing the culture apparatus of the fourth embodiment. Figure 24 This is a diagram showing a modified example of the culture apparatus according to the fourth embodiment. Detailed Implementation

[0016] "Table of contents" 1. An example of a common structure in all implementation methods 2. First Implementation Method 3. Second Implementation Method 4. Third Implementation Method 5. Fourth Implementation Method

[0017] 1. An example of a common structure in all implementation methods First, use Figures 1-9 This illustrates an example of a common structure of the culture apparatus involved in various embodiments of the present invention. Then, in Figure 10 From now on, each implementation method will be described using an example of a common structure as a premise.

[0018] like Figure 1 As shown, as an example of the culture object, the culture apparatus 10 according to the present invention cultivates hydroxide bacteria as microorganisms. The raw materials for the proliferation of hydroxide bacteria include hydrogen (H2), oxygen (O2), and carbon dioxide (CO2), as well as inorganic components such as ammonium sulfate. Hydrogen is an example of a flammable gas. The culture apparatus 10 causes the hydroxide bacteria to proliferate in the culture medium by supplying the raw material gas. Furthermore, in the culture medium, the hydroxide bacteria efficiently produce organic substances such as alcohols and amino acids by altering their genes. The organic substances produced in the culture medium are extracted by purifying the culture medium. The extracted organic substances are used, for example, in the manufacture of chemical products or biological products. Furthermore, the hydroxide bacteria are isolated from the culture medium, and the isolated hydroxide bacteria are being studied for use as feed, food, and fuel, for example.

[0019] like Figure 2 As shown, the culture apparatus 10 includes a culture tank 11, a raw material gas tank 12, a culture medium tank 13, a conditioning gas tank 14, a culture target tank 15, and a processor 17. The culture tank 11 contains a culture medium 18. For example, the hydroxyl-oxidizing bacteria 21 can be bacteria of the genus *Hydrogenophilus*, as described in Japanese Patent No. 6528295. In this case, the culture medium 18, as described in Japanese Patent No. 6528295, is, for example, an aqueous solution prepared by dissolving ammonium sulfate ((NH4)2SO4), potassium dihydrogen phosphate (KH2PO4), dipotassium hydrogen phosphate (K2HPO4), sodium chloride (NaCl), etc., in water. The culture tank 11 is an example of a "culture tank" according to the technology of this invention. Furthermore, regarding the raw material gas tank 12, a gas generating device for generating the raw material gas 26 can be provided instead or otherwise.

[0020] The culture tank 11 is connected to supply channels 12A, 13A, 14A, and 15A for the raw material gas tank 12, the culture medium tank 13, the adjustment gas tank 14, and the culture object tank 15, respectively. Each supply channel 12A, 13A, 14A, and 15A consists of piping and valves. Furthermore, each supply channel 12A, 13A, 14A, and 15A is equipped with a pump 22 and a flow meter 23 for measuring the flow rate of the fluid flowing through each supply channel.

[0021] The culture medium tank 13 contains culture medium 18. The culture medium 18 is supplied from the culture medium tank 13 to the culture tank 11 through the supply channel 13A by driving the pump 22 on the supply channel 13A. The timing and amount of the culture medium 18 are controlled by the processor 17 that controls the drive of the pump 22.

[0022] (Pretreatment of the culture medium in the culture medium tank) Furthermore, as an example, the culture medium tank 13 is equipped with a degassing device 13B. When culture medium 18 is replenished from the culture medium tank 13 to the culture tank 11, the degassing device 13B removes unwanted gases dissolved in the culture medium 18. Unwanted gases include, for example, air and nitrogen, gases that have adverse effects on the culture (such as a decrease in culture efficiency).

[0023] Alternatively, the culture medium tank 13 and the raw material gas tank 12 can be connected by piping, allowing raw material gas to be replenished to the culture medium 18 supplied to the culture tank 11. By pre-replenishing the culture medium 18 before it is supplied to the culture tank 11, the dissolved gas concentration of the raw material gas in the culture medium 18 supplied to the culture tank 11 can be increased. This can sometimes improve the culture efficiency. In this case, a dissolved gas concentration measuring unit (same as the dissolved gas concentration measuring unit 49 described later) can be installed in the culture medium tank 13 to measure the dissolved gas concentration of the raw material gas in the culture medium 18, and the amount of raw material gas replenished can be controlled based on the measured dissolved gas concentration.

[0024] The culture vessel 15 contains hydroxide bacteria 21, which is used as an example of a culture object. The hydroxide bacteria 21 are supplied from the culture vessel 15 to the culture tank 11 through the supply channel 15A by driving the pump 22 on the supply channel 15A. The timing and amount of supply of the hydroxide bacteria 21 are controlled by the processor 17 that controls the drive of the pump 22.

[0025] The raw material gas tank 12 contains raw material gas 26. As described above, for example, the raw material gas 26 is a gas containing hydrogen (H2), oxygen (O2), and carbon dioxide (CO2). The raw material gas 26 is supplied from the raw material gas tank 12 to the culture tank 11 through the supply channel 12A by driving the pump 22 on the supply channel 12A. The timing and amount of the raw material gas 26 supply are controlled by the processor 17 that controls the drive of the pump 22.

[0026] The downstream end of the supply channel 12A is disposed within the culture tank 11, and a distributor 28 is provided at the downstream end. The distributor 28 is used to disperse and supply the raw material gas 26 into the culture medium 18. As an example, the distributor 28 is a vent pipe formed of a porous material. The distributor 28 is an example of a bubble generating device that generates the raw material gas 26 in the form of bubbles within the culture medium 18. In addition to the microporous type such as the distributor 28, bubble generating devices also include various types such as the rotary liquid flow type that generates bubbles using a high-speed rotating flow, the ejector type (also known as the Venturi type) that generates bubbles using a rapid pressure change within the gas-liquid flow path, and the static mixer type that generates bubbles using the shear force of obstacles within the gas-liquid flow path. Other types besides the distributor 28 can also be used as bubble generating devices.

[0027] A portion of the raw material gas 26 supplied to the culture medium 18 dissolves in the culture medium 18. The dissolved raw material gas 26 is ingested by the hydroxide bacteria 21 and consumed in the proliferation of the hydroxide bacteria 21 or the production of organic matter 29. Organic matter 29 is, for example, alcohol or amino acids. The raw material gas 26 that is not dissolved in the culture medium 18 is released into the space 11A above the liquid surface 18A of the culture medium 18. The space 11A is filled with the raw material gas 26 that is not dissolved in the culture medium 18 and is released as mixed gas 31. The pump 22 on the raw material gas tank 12 and the supply channel 12A is an example of a "raw material gas supply unit".

[0028] The adjusting gas tank 14 contains adjusting gas 33. The adjusting gas 33 is supplied from the adjusting gas tank 14 through the supply channel 14A to the space 11A of the culture tank 11 by driving the pump 22 on the supply channel 14A. The timing and amount of the adjusting gas 33 supply are controlled by the processor 17 that controls the drive of the pump 22. The mixed gas 31 in the space 11A contains hydrogen and oxygen, which are components of the raw material gas 26. Hydrogen is a flammable gas. As described later, the adjusting gas 33 is used to maintain the composition ratio of the mixed gas 31 in the space 11A at a target value outside a predetermined explosion range.

[0029] Furthermore, the mixed gas 31 contains components of the feed gas 26. Therefore, a portion of the mixed gas 31 can be returned to the culture tank 11 via the gas circulation path 39 for reuse as feed gas 26. The mixed gas 31 reused as feed gas 26 is also supplied to the culture tank 11 via the distributor 28. The unreused mixed gas 31 is discharged. Additionally, although not shown in the figure, when discharging the unreused mixed gas 31, the mixed gas 31 is diluted with an inert gas such as carbon dioxide before being exposed to the atmosphere.

[0030] The culture tank 11 is connected to a discharge channel 36 for removing the mixed gas 31. The discharge channel 36 is equipped with a pump 22 and a three-way valve 38. The pump 22 generates pressure for discharging and circulating the mixed gas 31. The three-way valve 38 switches between a state where the discharge channel 36 is connected to the gas circulation path 39 and a state where the connection between the discharge channel 36 and the gas circulation path 39 is closed. The three-way valve 38 is used to switch whether the mixed gas 31 is sent to the gas circulation path 39 or discharged to the outside. Furthermore, the discharge channel 36 is equipped with a composition ratio measuring unit 16 for measuring the composition ratio of the mixed gas 31. The composition ratio measuring unit 16 is used for controlling the composition ratio of the mixed gas 31, as described later.

[0031] (Location of the outlet for the mixed gas) Furthermore, the gas outlet 34, which extracts the mixed gas 31 from the culture tank 11, is positioned to take in the foam layer 18B that covers the surface 18A of the culture medium 18 formed within the culture tank 11. The foam layer 18B functions as a liquid film covering the surface 18A and helps suppress explosions by increasing the heat capacity of the space 11A. However, on the other hand, besides adversely affecting various sensors and the like within the culture tank 11, there are concerns that the foam layer 18B may damage the hydroxide bacteria 21. Therefore, by positioning the gas outlet 34 to take in the foam layer 18B, a portion of the foam layer 18B can be recovered when the mixed gas 31 is extracted, thereby reducing the adverse effects caused by the foam layer 18B.

[0032] (Supply of each component of the raw gas) Furthermore, in Figure 2 In order to reduce the complexity of the accompanying drawings and for convenience, the supply channel 12A of the raw material gas 26 and the gas circulation path 39 of the mixed gas 31 are shown as a single line. However, in reality, as shown in the accompanying drawings... Figure 3 As shown, the supply channel 12A and gas circulation path 39 are separated according to each component, such as hydrogen, oxygen, and carbon dioxide, enabling the separate supply of multiple components. Each supply channel 12A and gas circulation path 39 for each component is equipped with a pump 22 and a flow meter 23. Furthermore, the distributors 28 are also arranged according to each component, such as hydrogen (H2), oxygen (O2), and carbon dioxide (CO2). Each supply channel 12A and gas circulation path 39 for each component is connected to a corresponding distributor 28 for that component.

[0033] (Removal of impurities from the feed gas) The connecting component 40 connects the supply channel 12A and the gas circulation path 39 upstream of the distributor 28 for each component. Thus, the supply channel 12A and the gas circulation path 39 are combined into one and connected to the distributor 28. An impurity removal mechanism 51 is provided between each connecting component 40 and each distributor 28. The impurity removal mechanism 51 removes impurities from the raw material gas 26 supplied to the culture tank 11. Impurities include sulfur oxides or nitrogen oxides (NO and NO2, etc.). The impurity removal mechanism 51 is a mechanism that uses any one of membrane separation, cryogenic separation, physical adsorption, and chemical absorption methods to separate impurities from the raw material gas 26.

[0034] exist Figure 2If the cultivation process continues, impurities will accumulate in the culture tank 11. As described later, a portion of the culture medium 18 in the culture tank 11 is temporarily removed and returned to the culture tank 11 for reuse. When the culture medium 18 circulates, the raw material gas 26 is separated from the culture medium 18, and the raw material gas 26 in the culture medium 18 is also returned to the culture tank 11 for reuse via the gas reuse path 62. In addition, a portion of the mixed gas 31 is also returned to the culture tank 11 for reuse via the gas circulation path 39. The gas reuse path 62 and the gas circulation path 39 are connected to the upstream side of the impurity removal mechanism 51. The reused mixed gas 31 and the separated gas separated from the culture medium 18 are supplied back to the culture tank 11 after impurities are removed by the impurity removal mechanism 51. In this way, while the raw material gas 26 is circulated, impurities are removed, thus suppressing the accumulation of impurities in the culture tank 11.

[0035] (Separation of components contained in a gas mixture) Furthermore, since the mixed gas 31 contains various components such as hydrogen, oxygen, and carbon dioxide, the gas circulation path 39 is equipped with a component separation mechanism 52 for separating the components contained in the mixed gas 31. The component separation mechanism 52 separates the components contained in the mixed gas 31, and the separated components are supplied to the respective gas circulation paths 39 arranged according to their components. The component separation mechanism 52 is a mechanism that uses any one of membrane separation, cryogenic separation, physical adsorption, and chemical absorption methods to separate the components from the mixed gas 31. The component separation mechanism 52 is an example of the "first component separation mechanism" involved in the technology of this invention.

[0036] Thus, when supplying the raw material gas 26 to the culture tank 11, the separate supply of hydrogen (H2), oxygen (O2), and carbon dioxide (CO2) offers advantages in both culture efficiency and safety. The advantage in culture efficiency lies in the ease with which the raw material gas 26 supplied to the culture tank 11 can be adjusted to an appropriate composition from a culture efficiency perspective. Furthermore, the safety advantage is as follows: Since the three elements of an explosion are flammable gas, oxygen, and an ignition source, hydrogen and oxygen, which are flammable gases, can be separated from the three elements of an explosion before supplying the raw material gas 26 to the culture tank 11, thereby further reducing the risk of explosion.

[0037] In addition, the component separation mechanism 52 can separate components such as nitrogen and methane, which are also components contained in the mixed gas 31, in addition to hydrogen, oxygen, and carbon dioxide. Nitrogen and methane have the effect of reducing the solubility of the raw material gas 26 in the culture medium 18. Therefore, when the mixed gas 31 is reused, separating them can improve the solubility of the raw material gas 26.

[0038] (Culture medium circulation, recovery and reuse) And, as Figure 2 as well as Figure 4 As shown, the culture tank 11 is connected to a culture medium circulation path 54, which is equipped with a culture medium recovery mechanism 55. The culture medium circulation path 54 removes a portion of the culture medium 18 from the culture tank 11. The culture medium recovery mechanism 55 recovers the culture medium 18 containing organic matter 29 from the culture medium 18 removed from the culture tank 11 via the culture medium circulation path 54. The culture medium circulation path 54 returns the remaining culture medium 18 containing hydroxide bacteria 21, after being recovered by the culture medium recovery mechanism 55, to the culture tank 11. Alternatively, in the case of purifying and proliferating hydroxide bacteria 21, the hydroxide bacteria 21 can be recovered, for example, in a manner different from that used for the organic matter 29.

[0039] (Separation of dissolved gases in the culture medium) A gas separation mechanism 61 is provided downstream of the culture medium recovery mechanism 55 on the culture medium circulation path 54. Before returning the culture medium 18 to the culture tank 11, the gas separation mechanism 61 separates a gas containing components of the raw material gas 26 contained in the culture medium 18 as a separated gas. Then, the culture medium 18 after separating the separated gas is returned to the culture tank 11. The gas separation mechanism 61 is a separation mechanism utilizing any one of membrane separation, cryogenic separation, physical adsorption, and chemical absorption methods. Hydrogen separation can utilize hydrogen storage alloys.

[0040] (Reusing raw material gases from the culture medium) A portion of the separated gas from the gas separation mechanism 61 is returned to the culture tank 11 via the gas reuse path 62 and the gas circulation path 39 of the mixed gas 31. It is then reused as feed gas 26. Therefore, the utilization efficiency of the feed gas 26 is improved.

[0041] (Explosion suppression when reusing raw material gases from culture medium) Furthermore, since the separated gas is returned to the culture tank 11 via the gas circulation path 39, it is separated into components such as hydrogen, oxygen, and carbon dioxide by the component separation mechanism 52 as described above. However, the separated gas can also be separated into components such as hydrogen, oxygen, and carbon dioxide within the gas reuse path 62, instead of being separated by component in the component separation mechanism 52. These separated components are then reused via the component-based gas circulation path 39. The separation of each component of the separated gas within the gas reuse path 62 can also be performed, for example, using the gas separation mechanism 61 that separates gas from the culture medium 18.

[0042] In this way, hydrogen and oxygen, which are flammable gases, can be separated during gas reuse, thus improving safety within the gas reuse path 62. Therefore, from a safety perspective, it is preferable to separate hydrogen, which is a flammable gas, from the culture medium 18 taken from the self-cultivation tank 11 as upstream as possible. Furthermore, as the order of separation, it is preferable to separate hydrogen first, followed by oxygen and carbon dioxide. This gas separation mechanism 61 has the function of suppressing explosions, and is therefore an example of an "explosion suppression mechanism" according to the technology of this invention.

[0043] Furthermore, if the components of the separated gas are separated in the gas separation mechanism 61 in this way, carbon dioxide, in addition to being reused as raw material gas 26, can also be returned to the conditioning gas tank 14 for reuse as conditioning gas 33. In the case of separating the separated gas into its components, the gas separation mechanism 61 is also an example of the "second component separation mechanism" according to the technology of this invention. Similar to the component separation mechanism 52, in the gas separation mechanism 61, in addition to hydrogen, oxygen, and carbon dioxide, components that reduce the solubility of the raw material gas 26, such as nitrogen and methane, can also be separated.

[0044] (The separation of specific components from the culture medium) And, as Figure 5 As shown, by utilizing the same separation mechanism 65 as the gas separation mechanism 61 and the component separation mechanism 52, in addition to separating gases from the culture medium 18, specific components contained in the culture medium 18 can also be separated. Examples of such specific components include ammonia and ammonium compounds. Ammonia and ammonium compounds serve as a nutrient source for the hydroxide bacteria 21. By separating them, the separated specific components can be reused while adjusting the supply rate.

[0045] In this way, by separating the various components contained in the mixed gas 31 and the culture medium 18, unnecessary components can be removed and usable components can be reused, thereby improving the culture efficiency and the utilization efficiency of the raw material gas 26.

[0046] exist Figure 4 In this system, the culture medium recovery mechanism 55 is connected to the recovery tank 57, which stores the recovered culture medium 18, i.e., the recovery liquid 58, via the recovery path 56. The recovery liquid 58 is transferred from the culture medium recovery mechanism 55 to the recovery tank 57 via the recovery path 56. The recovery path 56 is equipped with a pump 22 for transferring the recovery liquid 58.

[0047] A portion of the recovered liquid 58 contained in the recovered liquid tank 57 is transferred to a purification device (not shown). In the purification device, organic matter 29 produced by the cultivation of hydroxide bacteria 21 is extracted from the recovered liquid 58.

[0048] (Treatment to reduce the concentration of dissolved flammable gases in the recovered liquid) The culture apparatus 10 includes a concentration reduction mechanism that lowers the concentration of dissolved hydrogen in the recovered liquid 58 to a level lower than that of the culture liquid 18 in the culture tank 11. As an example, the concentration reduction mechanism is configured to extend the total length L of the section from the culture tank 11 to the culture liquid recovery mechanism 55 along the culture liquid circulation path 54 to the length required for concentration reduction. Specifically, the total length L of this section is the length required to reduce the concentration of dissolved hydrogen in the recovered liquid 58 to less than 1 / 10 of the concentration of dissolved hydrogen in the culture liquid 18 in the culture tank 11. The culture liquid 18 taken from the culture tank 11 contains hydrogen-consuming hydroxide bacteria 21, which also consume hydrogen within the culture liquid circulation path 54. The longer the culture liquid circulation path 54, the longer the time for hydrogen to be consumed by the hydroxide bacteria 21 can be ensured. This improves hydrogen utilization efficiency. Furthermore, if hydrogen is consumed in the section from the culture liquid circulation path 54 to the culture liquid recovery mechanism 55, the concentration of dissolved hydrogen in the recovered liquid 58 recovered by the culture liquid recovery mechanism 55 is reduced. As a result, the amount of hydrogen released from the recovery liquid 58 is reduced, thus decreasing the risk of explosion within the recovery liquid tank 57 and ensuring safety. The culture medium circulation path 54, with a total length L of the aforementioned interval and the length required for concentration reduction, is an example of the "concentration reduction mechanism" involved in the technology of this invention.

[0049] Furthermore, the flow rate of the culture medium 18 flowing through this section can be reduced instead of extending the total length L of the culture medium circulation path 54. This extends the time until the culture medium 18 removed from the culture tank 11 is transferred to the culture medium recovery mechanism 55, thus extending the time for hydrogen to be consumed within the removed culture medium 18. As a result, the same effect as extending the total length L of the section can be achieved. The flow rate of the culture medium 18 can be adjusted, for example, by controlling the suction rate of the pump 22 per unit time. The suction rate of the pump 22 is controlled by the processor 17. This flow rate adjustment mechanism, consisting of the processor 17 and the pump 22, is also an example of the "concentration reduction mechanism" involved in the technology of this invention.

[0050] (Downstream of recovery tank 57) Downstream of the recovery liquid tank 57, a purification target separation mechanism 59 is provided. This purification target separation mechanism 59 separates a portion of the recovery liquid 58 containing organic matter 29 as the purification target and sends the separated purification target to the purification device. The remaining recovery liquid 58, excluding the recovery liquid 58 separated by the purification target separation mechanism 59, is returned to the culture tank 11 as culture medium 18 via the liquid reuse path 63 and the culture medium circulation path 54 for reuse.

[0051] As in Figure 4As shown in the enlarged view, the culture medium recovery mechanism 55 includes a pump 22 and a liquid separation mechanism 64. The pump 22 generates circulating pressure to circulate the culture medium 18. Similar to the purification separation mechanism 59, the liquid separation mechanism 64 separates a portion of the culture medium 18 containing organic matter 29 from the culture medium 18 taken from the culture tank 11, and sends the separated culture medium 18 as recovery liquid 58 to the recovery path 56. The remaining culture medium 18 is sent to the gas separation mechanism 61.

[0052] (The location of the culture medium outlet on the culture medium circulation path) And, as Figure 6 As shown, the culture medium circulation path 54 has an outlet 54A for removing culture medium 18 from the culture tank 11 and a return outlet 54B for returning a portion of the removed culture medium 18 to the culture tank 11. The dissolved gas concentration of the feed gas 26 in the culture medium 18 within the culture tank 11 is low on the upper side in the height direction and high on the lower side. The outlet 54A is located in a low-concentration region with relatively low dissolved gas concentration, and the return outlet 54B is located in a high-concentration region with relatively high dissolved gas concentration. More specifically, the outlet 54A is located in a low-concentration region within the culture tank 11 where the dissolved gas concentration of the culture medium 18 is below the average value Av.

[0053] Therefore, when a portion of the culture medium 18 is removed from the culture tank 11 in order to circulate the culture medium 18, it is easy to eliminate the uneven concentration of dissolved gas in the culture medium 18 within the culture tank 11.

[0054] (Stirring, temperature adjustment, and sensing of various information in the culture tank) Furthermore, in Figure 2 In the culture tank 11, a stirring rod 41 is provided to stir the culture medium 18. The stirring rod 41 is a support rod with a propeller 41A mounted on it, and the propeller 41A is positioned inside the culture medium 18. The stirring rod 41 is driven by a motor 42 controlled by a processor 17 to rotate around the support rod as its rotation axis. This stirs the culture medium 18. By stirring the culture medium 18, the stirring rod 41 causes the hydroxide bacteria 21 and the raw material gas 26 in the culture medium 18 to diffuse, thus preventing local deviations.

[0055] Furthermore, the stirring rod 41 stirs the culture medium 18 to form bubbles from the culture medium 18, thereby forming the aforementioned foam layer 18B on the liquid surface 18A of the culture medium 18.

[0056] In addition, the culture tank 11 is equipped with a thermometer 46, a temperature regulator 47, a pressure gauge 48, a dissolved gas concentration measuring unit 49, and a density measuring unit 50. The thermometer 46 measures the temperature T in the culture solution 18. The temperature regulator 47 heats or cools the culture solution 18 in the culture tank 11. The pressure gauge 48 measures the pressure PS in the space 11A. The dissolved gas concentration measuring unit 49 measures the dissolved gas concentration Dr of the raw material gas 26 dissolved in the culture solution 18. The density measuring unit 50 measures the density ρ of the hydroxide bacteria 21 present in the culture solution 18 in the culture tank 11.

[0057] The culture medium 18 is maintained at a target temperature suitable for culturing the hydroxide bacteria 21. For example, the target temperature is above 40°C and below 95°C. The target temperature is set for each microorganism. In the case of the hydroxide bacteria 21 being a hydrogenophilic bacterium, approximately 50°C is more preferred. To achieve the target temperature, the culture medium 18 sometimes needs to be cooled in addition to heating. This is because the microorganisms being cultured sometimes generate heat during proliferation, causing the culture medium 18 to exceed the target temperature. The processor 17 controls the drive of the temperature regulator 47 based on the temperature T measured by the thermometer 46 to maintain the temperature T of the culture medium 18 at the target temperature.

[0058] Furthermore, the processor 17 controls the pressure of the mixed gas 31 within space 11A based on the pressure PS measured by the pressure gauge 48. By setting the pressure PS of the mixed gas 31 to the target pressure, the solubility of the raw material gas 26 in the culture medium 18 is improved. Thus, the processor 17 ensures appropriate solubility in the culture medium 18 by controlling the pressure of the mixed gas 31. Consequently, the cultivation efficiency of the hydroxide bacteria 21 is improved. The pressure PS of the mixed gas 31 is adjusted to at least one of the supply rate of the raw material gas 26, the discharge rate of the mixed gas 31, and the supply rate of the conditioning gas 33. The processor 17 adjusts the supply or discharge rate of these gases by controlling the drive of each pump 22.

[0059] More specifically, the dissolved gas concentration measuring unit 49 measures the concentration of each component (hydrogen, oxygen, and carbon dioxide) contained in the raw material gas 26 dissolved in the culture medium 18. For example, the dissolved gas concentration measuring unit 49 consists of a dissolved hydrogen meter (for example, manufactured by KYOEI Electronic Research Institute: model KM2100DH) for measuring dissolved hydrogen concentration (Dr(H2)), a dissolved oxygen meter (for example, manufactured by METTLER TOLEDO: model InPro6860i) for measuring dissolved oxygen concentration (Dr(O2)), and a dissolved carbon dioxide meter (for example, manufactured by METTLER TOLEDO: model InPro5000i) for measuring dissolved carbon dioxide concentration (Dr(CO2)). The dissolved gas concentration measuring unit 49 outputs the measured values ​​to the processor 17.

[0060] like Figure 3 As shown, the raw material gas tank 12 contains the raw material gas 26 according to its composition (hydrogen, oxygen, carbon dioxide). Furthermore, a supply channel 12A and a pump 22 are provided according to the composition.

[0061] The processor 17 acquires the measured value of the dissolved gas concentration of each component from the dissolved gas concentration measuring unit 49, compares the dissolved gas concentration with the target value by component, and supplies the insufficient components in the raw material gas 26 to the culture tank 11. The processor 17 can maintain the dissolved gas concentration of the raw material gas 26 in the culture medium 18 at an appropriate value by controlling the supply amount of each component of the raw material gas 26.

[0062] The density measuring unit 50 measures the density ρ of the cultured organisms present in the culture medium 18 within the culture tank 11. As an example, the density measuring unit 50 is composed of a total cell density sensor (as an example, manufactured by HAMILTON: model Dencytee RS485). In this example, the cultured organism is hydroxide bacteria 21, therefore the density measuring unit 50 measures the density ρ of hydroxide bacteria 21 within the culture medium 18. There is a positive correlation between the density ρ of hydroxide bacteria 21 and the amount of feed gas 26 consumed by hydroxide bacteria 21. By measuring the density ρ, for example, the amount of feed gas 26 consumed by hydroxide bacteria 21 can be calculated, or a process check can be performed to verify whether the amount of feed gas 26 consumed is appropriate relative to the amount of hydroxide bacteria 21.

[0063] The water level gauge 66 measures the water level of the culture medium 18 in the culture tank 11, that is, the height of the liquid surface 18A. Based on the water level of the culture medium 18 measured by the water level gauge 66, the amount of culture medium 18 present in the culture tank 11 can be determined. The water level gauge 66 is used for process checks to ensure the appropriateness of the amount of culture medium 18 and for calculating the necessary replenishment of the culture medium 18.

[0064] Furthermore, the culture tank 11 is equipped with an explosion vent 67. The explosion vent 67 is structured such that, in the event of an explosion within the culture tank 11, it safely releases the pressure within the culture tank 11 by failing earlier than other parts, thereby suppressing the spread of damage. The vicinity of the explosion vent 67 is selected at a location where significant damage will not occur even after pressure is released, or at a location where countermeasures to prevent the spread of damage have been implemented.

[0065] The processor 17 is composed of, for example, a CPU (Central Processing Unit) and RAM (Random Access Memory), and controls various parts of the culture apparatus 10 as described above. Furthermore, the memory 17A is a non-volatile memory such as flash memory that stores various setting information.

[0066] (Control of the bubble diameter of the raw material gas supplied to the incubator) Regarding the bubble diameter of the raw material gas 26 generated in the culture solution 18 of the culture tank 11, d90 is set to be below 1000 μm. For example... Figure 7 As shown, d90 refers to the bubble diameter that, when the volume is accumulated sequentially from the smallest bubble in the whole bubble system, becomes 90% of the total volume of all bubbles. Figure 7 The bar chart-based distribution of the mountain shape shown is a histogram of the bubble diameters generated in the culture medium 18, with the horizontal axis representing bubble diameter and the vertical axis representing frequency. If the volume of these bubble diameters is accumulated, it becomes... Figure 7 The graph shows a steadily increasing line graph. d90 is the bubble diameter that accounts for 90% of the total volume. In the culture apparatus 10, for example, this bubble diameter is set to 1000 μm or less. This bubble diameter is determined, for example, according to the specifications of the bubble generating device such as the distributor 28. Regarding the bubble diameter, by setting d90 to 1000 μm or less, the solubility of the feed gas 26 in the culture medium 18 can be improved. A more preferred bubble diameter is d90 of 500 μm or less, and even more preferably d90 of 200 μm or less. By setting this bubble diameter, even under conditions where the feed gas 26 is not easily soluble, such as when the temperature of the culture medium 18 is high or the depth of the culture tank 11 is shallow, high solubility of the feed gas 26 can be ensured.

[0067] (Surface tension reducing agent) And, as Figure 8As shown, the culture medium 18 can contain a surface tension reducer by adding a surface tension reducer. If the surface tension of the culture medium 18 decreases, the bubbles are more easily reduced in diameter, thus improving the solubility of the feed gas 26, which contains hydrogen as a combustible gas. The surface tension of the culture medium 18 is preferably set to 65 mN / m or less. With this level of surface tension, it is easy to set the bubble diameter d90 to 1000 μm or less. The amount of surface tension reducer added is determined in a way that achieves this surface tension value. More preferably, the surface tension of the culture medium 18 is 55 mN / m or less, and even more preferably 45 mN / m or less. By setting this surface tension, it is easier to reduce the bubble diameter.

[0068] (Reuse of waste gas) And, as Figure 9 As shown, the culture apparatus 10 can reuse exhaust gas containing carbon dioxide discharged from an external device as feed gas 26 for the culture apparatus 10. The external device is a device other than the culture apparatus 10; for example, it could be another device within the same facility as the facility where the culture apparatus 10 operates, or another device in another facility (such as a factory). In the case of reusing the exhaust gas, carbon dioxide is separated from the exhaust gas using a component separation mechanism 52, and the separated carbon dioxide is reused as feed gas 26. Thus, by reusing the carbon dioxide contained in the exhaust gas, it is possible to help reduce carbon dioxide emissions.

[0069] 2. First Implementation Method Taking one example of the above common structure as a premise, using Figures 10-16 The first embodiment of the culture apparatus 10 will be described. As a safety measure when using hydrogen, which is a flammable gas, the culture apparatus 10 of the first embodiment controls the composition ratio of the mixed gas 31, the solubility rate of hydrogen, and the consumption rate.

[0070] like Figure 10 As shown, measurement signals and detection signals from various sensors in the culture apparatus 10 are input to the processor 17. Furthermore, as culture condition information, the processor 17 stores various control target values ​​in its memory 17A. The processor 17 performs various controls by outputting control signals corresponding to the target values ​​to each part.

[0071] As target values ​​for various controls, there are target temperatures and target pressures for the culture medium 18. Furthermore, as examples of target values ​​outside the explosive range used for composition ratio control, these include target values ​​for hydrogen concentration (TD(H2)), oxygen concentration (TD(O2)), and water vapor concentration (not shown). In addition, the memory 17A contains target values ​​for hydrogen solubility (TRd(H2)) for hydrogen solubility control and target values ​​for hydrogen consumption rate (TRc(H2)) for hydrogen consumption rate control.

[0072] (Composition ratio control of mixed gas) As described above, hydrogen is a flammable gas, and the adjusting gas 33 is used to maintain the composition ratio of the mixed gas 31 within space 11A at a target value outside a predetermined explosion range. In the mixed gas 31, hydrogen, as a flammable gas, is mixed with oxygen. In this case, an explosion will occur depending on the composition ratio of the mixed gas 31. The composition ratio of the mixed gas at the time of explosion is called the explosion range. As described above, as the target values ​​outside the explosion range, the memory 17A of the processor 17 sets target values ​​for hydrogen concentration (TD(H2)), oxygen concentration (TD(O2)), and water vapor concentration, etc. The target values ​​outside the explosion range vary depending on the composition of the mixed gas 31. As in this example, when the mixed gas 31 is a mixture containing hydrogen and oxygen, the target values ​​outside the explosion range are typically less than 5% oxygen concentration or less than 4% hydrogen concentration in the mixed gas 31.

[0073] Furthermore, the applicant has experimentally verified that if the water vapor concentration is 7% or higher, the composition of the gas mixture can be maintained outside the explosion range even if the oxygen concentration is 5% or higher. Therefore, in this example, regarding the target value outside the explosion range, if the water vapor concentration is 7% or higher and 90% or lower, the oxygen concentration is set within the range of 5% or higher and 9% or lower.

[0074] The experiment was conducted as follows. A stainless steel chamber with an inner diameter of 200 mm, a depth of 200 mm, and a volume of 6 L was used as the explosion container. Hydrogen, oxygen, carbon dioxide, and water vapor were filled into the explosion container (the water vapor was obtained by injecting water into the explosion container and evacuating it to the saturated vapor pressure at the container's internal temperature, causing the water to vaporize; the hydrogen, oxygen, and carbon dioxide were filled from gas cylinders via gas inlet piping installed in the explosion container). After homogenizing the gas by rotating a stirring fan inside the explosion container, ignition of the gas was attempted using a wire detonation device installed in the explosion container. Ignition or non-ignition was determined based on the presence of a pressure rise and the generation of negative pressure inside the explosion container due to water formation. The pressure was measured using a pressure sensor (KYOWA ELECTRONIC INSTRUMENTS CO., LTD., PHS-B-10MP) installed on the upper valve of the gas outlet piping installed in the explosion container.

[0075] Table 1 shows the experimental results regarding whether ignition occurred based on the gas concentration of the mixed gas. Both Example 1 and Comparative Example 1 in Table 1 are examples where the water vapor concentration is 0%, and the concentrations other than oxygen are almost identical. In Example 1, which did not ignite, the oxygen concentration was 4%, less than 5%, while in Comparative Example 1, which ignited, the oxygen concentration was 9%, exceeding 5%. Through Example 1 and Comparative Example 1, as is generally known, the following experimental results were obtained: when the water vapor concentration is 0%, ignition will not occur if the oxygen concentration is less than 5%.

[0076] Furthermore, Examples 2, 3, and Comparative Example 2 all had a water vapor concentration of 7% or higher, differing only in their oxygen concentrations. The oxygen concentrations in Examples 2 and 3 were 9%, while the oxygen concentration in Comparative Example 2 was 16%, exceeding 9%. Based on these experimental results, it can be concluded that even if the oxygen concentration is 5% or higher, and below 9%, a fire will not occur when the water vapor concentration is 7% or higher.

[0077] [Table 1]

[0078] Furthermore, Table 1 does not contain experimental results for cases where the hydrogen concentration is less than 4%. However, it is known that if a hydrogen concentration of less than 4% is used instead of setting the oxygen concentration to less than 5%, the gas mixture will not ignite even when the water vapor concentration is 0%. Therefore, as a target value outside the explosion range, the hydrogen concentration of gas mixture 31 can be set to less than 4% instead of setting the oxygen concentration of gas mixture 31 to less than 5%.

[0079] The adjusting gas 33 is, for example, an inert gas. More specifically, in this example, carbon dioxide (CO2) is used. By supplying the adjusting gas 33 to space 11A, the oxygen or hydrogen concentration decreases, and the composition ratio of the mixed gas 31 is maintained at a target value outside the explosion range. Alternatively, any gas other than an inert gas can be used as the adjusting gas 33. For example, any gas can be used to set the composition ratio of the mixed gas 31 to a target value outside the explosion range, such as using hydrogen, a flammable gas, to set the oxygen concentration of the mixed gas 31 to less than 5%. Thus, any gas can be used as the adjusting gas 33, but as described above, when reusing the mixed gas 31, the adjusting gas 33 preferably uses the composition of the raw material gas 26.

[0080] like Figure 11 As shown, the composition ratio measuring unit 16 is disposed on the discharge channel 36 from the space 11A of the culture tank 11, through which the mixed gas 31 is discharged. The composition ratio measuring unit 16 is, for example, composed of a gas analyzer for measuring hydrogen concentration (D(H2)) (for example, manufactured by HORIBA, Ltd.: model TCA-51d), a gas analyzer for measuring oxygen concentration (D(O2)) (for example, manufactured by HORIBA, Ltd.: model VA-5113), a gas analyzer for measuring carbon dioxide concentration (D(CO2)) (for example, manufactured by HORIBA, Ltd.: model VA-5113), and a flow meter for measuring the total flow rate (Qout(total)) of the mixed gas 31 (for example, manufactured by Emerson: model CMFS007M). Therefore, the composition ratio measuring unit 16 can measure the concentration and total flow rate of each component in the mixed gas 31. The composition ratio measuring unit 16 outputs each measured value to the processor 17 as a measurement signal.

[0081] The processor 17 determines the supply amount of adjusting gas 33 based on measurements of the total flow rate and oxygen concentration of the mixed gas 31, so that the oxygen concentration of the mixed gas 31 is maintained below a preset upper limit. Then, the processor 17 supplies the determined supply amount of adjusting gas 33 from the adjusting gas tank 14 to the space 11A via the pump 22. As a result, the supply amount of carbon dioxide (Qin(CO2)) in the space 11A increases, the relative oxygen concentration (D(O2)) decreases, and the composition ratio of the mixed gas 31 in the space 11A is maintained at a target value (TD(O2)) outside the preset explosive range. By increasing the supply amount of adjusting gas 33, the hydrogen concentration (D(H2)) also decreases, thus maintaining the hydrogen concentration at the target value (TD(O2)) outside the explosive range as well. The processor 17, the adjusting gas tank 14, and the pump 22 on the supply channel 14A are examples of a "composition ratio control mechanism" according to the technology of this invention.

[0082] Furthermore, since both the culture medium 18 and the space 11A are present within the culture tank 11, by maintaining the temperature T of the culture medium 18 at the target temperature, the temperature within the space 11A can also be maintained at almost the same temperature. As will be described later, the composition ratio of the mixed gas 31 within the space 11A is maintained at a target value outside a pre-set explosion range. The target value also includes the water vapor concentration of the mixed gas 31. By controlling the temperature of the culture medium 18 to above 40°C, the temperature of the mixed gas 31 can be set to above 40°C. Consequently, the water vapor concentration of the mixed gas 31 can also be adjusted to above 7%.

[0083] (Control of the solubility of flammable gases) like Figure 12 As shown, as an example of combustible gas solubility control, a solubility control mechanism including processor 17 performs hydrogen solubility control. Processor 17, composition ratio measuring unit 16, and flow meter 23 are examples of the "solubility control mechanism" involved in the technology of this invention.

[0084] The solubility control mechanism measures the proportion of hydrogen dissolved in the culture liquid 18 from the hydrogen in the raw gas supplied to the culture tank 11 via the gas circulation path 39 or the raw gas supply unit during cultivation, which is the hydrogen solubility rate, and maintains the measured hydrogen solubility rate (Rd(H2)) above a preset target value (TRd(H2)). When the amount of hydrogen discharged from the culture tank 11 as mixed gas 31 is set as Qout(H2) and the amount of hydrogen supplied to the culture tank 11 is set as Qin(H2), the hydrogen solubility rate (Rd(H2)) is defined by the following formula (1). Rd(H2)(%)=(1-Qout(H2) / Qin(H2))×100…Equation (1)

[0085] That is, the amount of hydrogen dissolved in the culture medium 18 is obtained by subtracting the amount of hydrogen discharged from the culture tank 11 from the amount of hydrogen supplied to the culture tank 11, and the ratio of the amount of dissolved hydrogen to the amount of supplied hydrogen is the hydrogen solubility rate.

[0086] Qout(H2) is the value obtained by multiplying the total amount of mixed gas 31 discharged from the culture tank 11 (Qout(total)) by the hydrogen concentration of mixed gas 31 (D(H2)). The processor 17 obtains Qin(H2) from the flow meter 23, and obtains Qout(total) and hydrogen concentration (D(H2)) from the composition ratio measuring unit 16, and determines the hydrogen solubility (Rd(H2)) based on the obtained measured values.

[0087] Then, as an example, the processor 17 controls, for instance, the amount of hydrogen supplied to the culture tank 11 (Qin(H2)) to maintain the hydrogen solubility (Rd(H2)) above the target value (TRd(H2)). By reducing the amount of hydrogen supplied to the culture tank 11, the hydrogen solubility (Rd(H2)) can be increased according to the definition of equation (1). As an example, the target value of the hydrogen solubility is preferably 90% or more.

[0088] If the solubility of hydrogen is increased, the amount of hydrogen released into space 11A decreases. By controlling the solubility in addition to the composition ratio control mechanism of the mixed gas 31, the hydrogen concentration in the mixed gas 31 can be further reduced, thus reducing the risk of explosion and improving safety compared to the past. This control is an effective technique when using raw material gas 26 containing flammable gases such as hydrogen.

[0089] (Control of flammable gas consumption rate) Furthermore, such as Figure 12 As shown, the solubility control mechanism can also control the hydrogen consumption rate through solubility control.

[0090] Specifically, the solubility control mechanism measures the hydrogen consumption rate of hydrogen consumed by the hydrogen-oxidizing bacteria 21 in the raw material gas 26, which is a combustible gas, supplied to the culture tank 11 through the gas circulation path 39 or the raw material gas supply unit during cultivation, and maintains the measured hydrogen consumption rate (Rc(H2)) at the target value (TRc(H2)) of 90% or more by controlling the hydrogen solubility rate.

[0091] When the hydrogen consumption of the hydroxide bacteria 21 in the culture tank 11 is set as Qcs(H2), the hydrogen consumption rate (Rc(H2)) is defined by the following formula (2). Rc(H2)(%)=Qcs(H2) / Qin(H2)×100…Equation (2)

[0092] That is, the ratio of the amount of hydrogen consumed by the hydroxide bacteria 21 in the culture tank 11 to the amount of hydrogen supplied to the culture tank 11 is the hydrogen consumption rate.

[0093] The difference between the amount of hydrogen supplied to culture tank 11, i.e., Qin (H2), and the amount of hydrogen discharged from culture tank 11, i.e., Qout (H2), represents the amount of hydrogen dissolved in culture medium 18. The amount of hydrogen dissolved in culture medium 18 includes not only the amount consumed by the hydroxide bacteria 21, i.e., Qcs (H2), but also the amount of dissolved hydrogen present in culture medium 18 that has not been consumed. Therefore, if the amount of dissolved hydrogen is set as Qr (H2), then Qcs (H2) = Qin (H2) - (Qout (H2) + Qr (H2)). Here, the amount of dissolved hydrogen Qr (H2) refers to the change relative to the amount of dissolved hydrogen used as a reference. For example, when Qcs (H2), Qin (H2), and Qout (H2) are set as the hydrogen consumption per minute, the hydrogen supply per minute, and the hydrogen discharge per minute, respectively, the amount of dissolved hydrogen Qr (H2) refers to the change relative to the amount of dissolved hydrogen (the amount of hydrogen dissolved in culture medium 18) one minute ago.

[0094] If the volume of the culture medium 18 contained in the culture tank 11 is set as Qm, the dissolved hydrogen amount (Qr(H2)) is obtained by multiplying the volume of the culture medium 18 (Qm) by the dissolved hydrogen concentration (Dr(H2)). The processor 17 calculates the volume of the culture medium 18 (Qm) based on the water level obtained from the water level gauge 66, and obtains the dissolved hydrogen concentration (Dr(H2)) measured by the dissolved gas concentration measuring unit 49, thereby measuring the dissolved hydrogen amount (Qr(H2)). Then, the processor 17 measures the hydrogen consumption (Qcs(H2)) and the hydrogen consumption rate (Rc(H2)) according to equation (2).

[0095] The solubility control mechanism, including processor 17, maintains the hydrogen consumption rate (Rc(H2)) at a target value (TRc(H2)) of over 90% by reducing the hydrogen supply through solubility control. By increasing the hydrogen consumption rate, the utilization efficiency of the feedstock gas 26 is improved.

[0096] refer to Figure 13 The flowchart shown in Figures 1-15 illustrates the function of the above structure. Figure 13The sequence of composition ratio control processing is indicated. For example, processor 17 heats the culture medium 18 to a target temperature by activating temperature regulator 47 while the culture tank 11 contains a culture medium 18 containing hydroxide bacteria 21. After the culture medium 18 reaches the target temperature, processor 17 begins supplying raw material gas 26, thereby initiating the culture process. After the culture process begins, processor 17 also controls the temperature of the culture medium 18 at the target temperature via temperature regulator 47. During the culture process, hydroxide bacteria 21 multiply by ingesting the raw material gas 26 dissolved in the culture medium 18, thereby producing organic matter 29. Hydroxyhydric bacteria 21 efficiently produce organic matter 29 by altering their genes. The moment when hydroxide bacteria 21 produce organic matter 29 is during or after multiplication. A portion of the raw material gas 26 undissolved in the culture medium 18 is released into the space 11A above the liquid surface 18A of the culture medium 18, becoming mixed gas 31.

[0097] In step S101 of the composition ratio control process, the processor 17 obtains the concentration of each component of the mixed gas 31 and the total flow rate of the mixed gas 31 from the composition ratio measuring unit 16. Then, the processor 17 calculates the oxygen concentration of the mixed gas 31 based on the obtained measurement values ​​and obtains this value as the composition ratio of the mixed gas 31.

[0098] In step S102, the processor 17 determines whether the composition ratio of the mixed gas 31 is outside the explosion range. As described above, in this example, the target value outside the explosion range is set to an oxygen concentration of 5% or more and 9% or less, and a water vapor concentration of 7% or more. Furthermore, in this example, the target temperature of the culture medium 18 is set to 40°C or more. Therefore, if the saturated water vapor content at 40°C is converted to a water vapor concentration, it is approximately 7%. Thus, as long as the target temperature of the culture medium 18 is set to 40°C or more, the water vapor concentration of the mixed gas 31 can be adjusted to 7% or more. The processor 17 compares the oxygen concentration derived from the measurement value of the composition ratio measuring unit 16 with the target value. If the oxygen concentration is within the range of the target value, it is determined that the composition ratio is outside the explosion range ("Yes" in step S102), and the process proceeds to step S104.

[0099] On the other hand, if the oxygen concentration exceeds the upper limit of the target value, i.e., 9%, the processor 17 determines that the composition ratio of the gas mixture 31 is within the explosive range ("No" in step S102) and proceeds to step S103. In step S103, the processor 17 supplies the adjusting gas 33 to the space 11A by driving the pump 22 of the supply channel 14A. As a result, the oxygen concentration of the gas mixture 31 decreases, and the composition ratio of the gas mixture 31 can be restored to outside the explosive range.

[0100] The processor 17 repeatedly performs this composition ratio control process until the cultivation process ends ("Yes" in step S104). As a result, the composition ratio of the mixed gas 31 in space 11A can be maintained at a target value outside the explosion range.

[0101] Furthermore, during the cultivation process, processor 17 executes... Figure 14 The solubility control process is shown. First, in step S201, processor 17 measures the hydrogen solubility (Rd(H2)) in culture tank 11 according to equation (1). Then, in step S202, processor 17 compares the measured hydrogen solubility (Rd(H2)) with the target value (TRd(H2)) and determines whether the hydrogen solubility (Rd(H2)) is above the target value (TRd(H2)). If the hydrogen solubility (Rd(H2)) is below the target value (TRd(H2)) ("No" in step S202), processor 17 proceeds to step S203 and reduces the hydrogen supply (Qin(H2)). Processor 17 maintains the hydrogen solubility (Rd(H2)) above the target value (TRd(H2)) through step S203. Processor 17 repeats this process until the culture process ends (step S204).

[0102] Furthermore, processor 17 performs processing via solubility control. Figure 15 The consumption rate control process is shown. First, in step S301, processor 17 measures the hydrogen consumption rate (Rc(H2)) in culture tank 11 according to equation (2). Then, in step S302, processor 17 compares the measured hydrogen consumption rate (Rc(H2)) with the target value (TRc(H2)) and determines whether the hydrogen consumption rate (Rc(H2)) is above the target value (TRc(H2)). If the hydrogen consumption rate (Rc(H2)) is below the target value (TRc(H2)) (in step S302, "No"), processor 17 proceeds to step S303. Then, in step S303, processor 17 reduces the hydrogen supply (Qin(H2)) in the same manner as in step S203 of the solubility control process. Processor 17 maintains the hydrogen consumption rate (Rc(H2)) above the target value (TRc(H2)) through step S303. Processor 17 repeats this process until the culture process ends (step S304).

[0103] As described above, the culture apparatus 10 of the first embodiment of the present invention includes a composition ratio control mechanism for the mixed gas 31 and a solubility control mechanism for hydrogen (an example of a flammable gas). Through the composition ratio control mechanism, the composition ratio of the mixed gas 31 within the culture tank 11 is maintained at a target value outside the explosion range, thus improving safety compared to conventional methods.

[0104] And, as Figure 16As shown, by controlling the solubility rate, the solubility rate of hydrogen in the culture medium 18 within the culture tank 11 is maintained above the target value, thus reducing the amount of hydrogen released into space 11A and decreasing the amount of hydrogen contained in the mixed gas 31. This further improves safety. The culture apparatus 10 of the first embodiment performs both composition ratio control and solubility rate control of the mixed gas 31, therefore offering higher safety compared to the case where the dissolved oxygen concentration in the culture medium 18 is controlled individually, as disclosed in Japanese Patent No. 2564008, which is prior art. Figure 16 As shown, by controlling the dissolution rate, the utilization efficiency of the raw material gas 26 can be improved.

[0105] Furthermore, in the culture apparatus 10 of the first embodiment, the advantages of controlling the composition ratio and solubility of the combined mixed gas 31 are as follows. For example, when controlling the composition ratio of the mixed gas 31 alone without controlling the solubility, the supply amount of the adjusting gas 33 required to maintain the hydrogen and oxygen concentrations at target values ​​outside the explosion range sometimes increases. If the supply amount of the adjusting gas 33 increases, the discharge amount of the mixed gas 31 also increases. Even if the mixed gas 31 is reused, there is a limit to the amount that can be reused, and the mixed gas 31 exceeding this limit must be exposed to the atmosphere. In this case, the adjusting gas 33 used to deactivate the mixed gas 31 is wasted.

[0106] If the composition ratio and solubility are controlled, the amount of hydrogen released into space 11A is reduced. Therefore, as Figure 16 As shown, in the composition ratio control of the mixed gas 31, the supply of adjusting gas 33 required to maintain the hydrogen or oxygen concentration at the target value outside the explosion range can be reduced. Thus, by combining the composition ratio control and solubility control of the mixed gas 31, the waste of adjusting gas 33 can be reduced.

[0107] Furthermore, the culture apparatus 10 of the first embodiment does not simply reduce the amount of hydrogen supplied, but rather uses the solubility rate as an indicator to control the amount of hydrogen supplied. Hydrogen that is not dissolved in the culture medium 18 will not be consumed by the hydroxide bacteria 21, which are the subjects of the culture, but will be released uselessly. By reducing the amount of hydrogen supplied using the solubility rate as an indicator, the culture apparatus 10 of the first embodiment can reduce the amount of hydrogen released uselessly. Therefore, concerns about insufficient raw materials for the hydroxide bacteria 21 are reduced, and the utilization efficiency of hydrogen as the raw material gas 26 is also improved.

[0108] By setting the target solubility rate to 90%, safety is further improved. Furthermore, by controlling the hydrogen consumption rate, the utilization efficiency of the feedstock gas 26 can be further improved.

[0109] In the above example, reducing the hydrogen supply was used as an example of solubility control. However, another method to improve solubility is to lower the temperature of the culture medium 18. By adjusting the temperature of the culture medium 18, the solubility of hydrogen can be changed. Furthermore, multiple bubble generating devices with different bubble diameters can be provided (for example, distributor 28), and the solubility can be controlled by selectively switching them. This is because, as mentioned above, the smaller the bubble diameter, the higher the solubility.

[0110] Furthermore, in order to maintain the solubility above the target value, with Figure 7 The combination of the bubble diameter settings shown is effective. And, similarly, as... Figure 8 As shown, the strategy of reducing surface tension by adding a surface tension reducer to the culture medium 18 is also effective.

[0111] Furthermore, in the first embodiment, as an example, hydroxide bacteria 21 were used as the culture medium, and the raw material gas 26 contained hydrogen as a flammable gas and oxygen and carbon dioxide as other components. The technology of the present invention is particularly effective in this combination of culture medium and raw material gas 26. This is because, firstly, the raw material gas 26 contains oxygen as an oxidizing gas, in addition to hydrogen as a flammable gas. Therefore, measures to suppress explosions are crucial for safety, and thus the technology of the present invention, which can further improve safety, is particularly effective.

[0112] Furthermore, since the raw material gas 26 contains carbon dioxide, which is an inert gas, by using carbon dioxide as the conditioning gas 33, the conditioning gas 33 can be reused as the raw material gas 26. Therefore, in terms of utilization efficiency, the technology of the present invention is also effective under this combination.

[0113] Furthermore, in the culture apparatus 10 of the first embodiment, in one example of a common structure, by means of... Figure 2 and Figure 3 The component separation mechanism 52 shown and Figure 2 and Figure 4 The gas separation mechanism 61 shown is combined in a way that effectively improves both safety and the utilization efficiency of the raw material gas 26. Firstly, regarding safety, since flammable gases can be separated, the safety of the gas circulation path 39 and the gas reuse path 62 is easily ensured. Furthermore, by separating specific components from the mixed gas 31, reuse corresponding to a specific purpose is easily achieved.

[0114] Furthermore, in the culture apparatus 10 of the first embodiment, in one example of a common structure, such as... Figure 2As shown, a technique is employed that positions the mixed gas outlet 34 of the gas circulation path 39 at a location capable of ingesting the foam layer 18B. This technique is effective in reducing adverse effects on sensors and the like while enabling accurate control.

[0115] Furthermore, in the culture apparatus 10 of the first embodiment, in one example of a common structure, it incorporates... Figure 4 The concentration reduction mechanism shown is for the culture medium 18 removed from the culture tank 11. This technology is effective in improving the safety of the downstream recovery path 56 and the recovery tank 57 of the culture medium recovery mechanism 55.

[0116] Furthermore, in the culture apparatus 10 of the first embodiment, in one example of a common structure, it incorporates... Figure 2 and Figure 4 The explosion suppression mechanism is shown in the figure. This technology is effective in improving safety in the gas reuse path 62.

[0117] Furthermore, as an explosion suppression mechanism, a gas separation mechanism 61 for separating hydrogen from the separated gas separated from the self-cultivation solution 18 is exemplified, but other structures can also be considered as explosion suppression mechanisms. For example, a structure can be considered where, when the gas to be reused is transferred in the gas reuse path 62, the composition ratio of the gas to be reused is controlled to a target value outside the explosion range, for example, by adding an inert gas such as the adjustment gas 33. Furthermore, it is also possible to consider forming an explosion suppression mechanism by setting a structure that minimizes the possibility of ignition sources from the gas reuse path 62. For example, a pump 22 with a mechanically movable part that generates frictional heat could potentially become an ignition source. Alternatively, as shown in the fourth embodiment described later, this pump 22 can be replaced with a pressure-applying device without a movable part (…). Figure 23 and Figure 24 The explosion suppression mechanism is implemented by methods such as the fluid injectors 75, 76, etc. shown.

[0118] Furthermore, in the culture apparatus 10 of the first embodiment, not all of the elements shown as a common structure may be provided; only a portion may be combined.

[0119] 3. Second Implementation Method use Figures 17-21 The culture apparatus 10 of the second embodiment will be described. In the second embodiment, the culture apparatus 10 of the second embodiment will be described. Figures 1-9 An example of the common structure shown and Figures 10-16 The structures described in the first embodiment shown are omitted and are marked with the same symbols.

[0120] The culture apparatus 10 of the second embodiment is a combination of the composition ratio control mechanism of the first embodiment and, as in the example... Figure 17The structure is formed by the longitudinally elongated culture tank 111 shown. More specifically, regarding the culture tank 111 of the second embodiment, when the equivalent circle diameter of the cross section orthogonal to the height direction of the culture tank 111 is set as DAm, and the maximum height of the liquid surface 18A is set as H, the dimensions of the culture tank 111 satisfy the dimensional condition H / DAm≥2. The height direction is the vertical direction.

[0121] Here, "equivalent circle diameter" refers to the diameter of the circle when the cross-section is circular, the diameter of the circumscribed circle when the cross-section is polygonal, and the major axis when the cross-section is ellipse or oblong. "Maximum height of the liquid level" refers to the height of the liquid level 18A of the culture medium 18 when the maximum capacity of the culture medium 18 is contained in the culture tank 111. The maximum capacity refers to the maximum capacity capable of performing the culture process. The maximum height of the liquid level 18A is the height measured with all sensors, such as the level gauge 66, immersed in the culture medium 18 and with all elements causing changes in the liquid level 18A, such as the stirring rod 41 and the distributor 28, completely stopped.

[0122] By using a longitudinally elongated culture tank 111 with these dimensions, the solubility of flammable gases is increased. The raw material gas 26 supplied to the culture solution 18 rises towards the liquid surface 18A. As it rises, a portion dissolves in the culture solution 18, while the undissolved raw material gas 26 is released into the space 11A above the liquid surface 18A, becoming a component of the mixed gas 31. Therefore, the longer the culture tank 111, the more sufficient the dissolution time of the raw material gas 26 is ensured, thus increasing the amount of raw material gas 26 dissolved in the culture solution 18. Consequently, the amount of raw material gas 26 contained in the mixed gas 31 decreases. In cases where the raw material gas 26 contains flammable gases, the amount of flammable gases contained in the mixed gas 31 decreases. This reduces the risk of explosion and improves safety.

[0123] In the second embodiment, by using a longitudinally elongated culture tank 111, the solubility of flammable gases is also increased. For example... Figure 16 As shown, by increasing the solubility of the combustible gas, the utilization rate of the raw material gas 26 also increases. Furthermore, by combining this with composition ratio control, it also has the effect of reducing the supply amount of the adjustment gas 33. This effect is the same as in the first embodiment.

[0124] The culture tank 111 is a bottomed cylindrical shape. Compared to a cylindrical shape with a polygonal cross-section, the cylindrical shape makes it easier to reduce the deviation in the concentration distribution of the culture medium 18. Furthermore, the cylindrical shape is easier to manufacture than a polygonal cylindrical shape.

[0125] Furthermore, the preferred dimensional condition is H / DAm ≥ 13. As a result, the culture tank 111 becomes longer and the solubility of flammable gases is further improved.

[0126] Furthermore, in the second embodiment, in one example of a common structure, such as Figure 7 As shown, regarding the bubble diameter of the raw material gas 26, d90 is preferably 1000 μm or less. This is because, assuming the size condition of the culture tank 111 is H / DAm=2, by setting d90 to 1000 μm or less, the bubbles will become almost disappearing near the liquid surface 18A.

[0127] Furthermore, in the second embodiment, reducing the bubble diameter by adding a surface tension reducing agent is also effective.

[0128] And, as Figure 17 As shown, the overall dimension of the temperature regulator 47 in the height direction of the culture tank 111 is preferably 30% or more of the maximum height of the liquid surface 18A. That is, if the length of the temperature regulator 47 in the height direction is Ht, it is preferable to satisfy the condition that Ht / H ≥ 30%. Here, "overall" means both the case where the continuous length Ht of a single temperature regulator 47 is 30% or more and the case where the total length of each segment is 30% or more when multiple temperature regulators 47 are arranged in a segmented configuration.

[0129] When the culture tank 111 is longitudinal, from the viewpoint of reducing temperature unevenness in the height direction, it is preferable that the temperature regulator 47 also has a length of more than 30% of the height H of the liquid surface 18A.

[0130] Furthermore, the temperature regulator 47 can have various shapes and can be configured to surround the outer periphery of the culture tank 111. For example, if the culture tank 111 is cylindrical, the temperature regulator 47 is also cylindrical. Alternatively, multiple temperature regulators 47 with arc-shaped cross-sections can be configured around the outer periphery of the culture tank 111.

[0131] And, as Figure 18 As shown in the modified example, the temperature regulator 47 can also be configured inside the culture tank 111. Of course, as... Figure 18 As shown, the temperature regulator 47 can also be configured both inside and outside the culture tank 111.

[0132] like Figure 18 As shown, at least a portion of the temperature regulator 47 is preferably disposed within the culture tank 111. This is because the temperature regulator 47 regulates the temperature of the culture medium 18 within the culture tank 111; therefore, disposing the temperature regulator 47 within the culture tank 111 results in better energy efficiency compared to disposing it outside the culture tank 111. The temperature regulator 47 within the culture tank 111 may be, for example, cylindrical. Of course, multiple arc-shaped temperature regulators 47 may also be disposed. Furthermore, in Figure 18 And as will be discussed later Figure 20In the diagram, the shape of the temperature regulator 47 disposed on the outside of the culture tank 111 is simplified. In reality, the temperature regulator 47 disposed on the outside of the culture tank 111 has, for example, an arc-shaped cross-section in the horizontal direction orthogonal to the height direction, and is curved along the outer peripheral surface of the culture tank 111.

[0133] As described above, the temperature regulator 47 is controlled by the processor 17, which adjusts the temperature of the culture medium 18 to a suitable temperature for cultivation. The temperature of the culture medium 18 can be maintained at a constant temperature during cultivation, or the temperature can be changed according to the progress of cultivation.

[0134] And, as Figure 19 As shown in the modified example, multiple temperature regulators 47 can also exist, with each temperature regulator 47 disposed at different positions along the height of the culture tank 111. Since the culture tank 11 is longitudinally long, it is preferable to arrange multiple temperature regulators 47 at different heights from the viewpoint of reducing temperature unevenness along the height direction. Furthermore, in Figure 19 In the figure, symbols Ht1 and Ht2 represent the lengths of the two temperature regulators 47 arranged side by side along the height direction in the respective height direction.

[0135] And, as Figure 20 As shown in the modified example, a stirring rod 41 with multiple propellers 41A is provided, and the multiple propellers 41A can be arranged at different positions in the height direction of the culture tank 111. The propellers 41A are an example of the "stirring part" involved in the technology of the present invention, and the stirring rod 41 is an example of the "stirring mechanism".

[0136] If multiple propellers 41A are arranged at different heights, the uneven concentration of substances dissolved or dispersed in the culture medium 18 along the height direction is reduced, which is therefore preferable. The substances dissolved or dispersed in the culture medium 18 are culture objects (microorganisms or cells) such as hydroxide bacteria 21 and raw material gases 26.

[0137] And, as Figure 21 As shown, with multiple temperature regulators 47 and multiple propellers 41A, multiple pairs of combinations of at least one temperature regulator 47 and at least one propeller 41A can be arranged at different positions in the height direction of the culture tank 111. In this way, both temperature unevenness and concentration unevenness can be reduced.

[0138] Alternatively, the solubility control mechanism of the first embodiment can be combined with the culture apparatus 10 of the second embodiment. By combining the longitudinally elongated culture tank 111 and the solubility control mechanism, the amount of flammable gas contained in the mixed gas 31 can be further reduced. As a result, the risk of explosion of the mixed gas 31 is reduced, and safety is further improved. Furthermore, by further increasing the solubility of the flammable gas, the consumption rate of the hydrogen from the hydroxide bacteria 21 and the consumption rate of the raw material gas 26 will also increase, thus improving the utilization efficiency of the raw material gas 26.

[0139] When controlling the solubility rate, similar to the first embodiment, the target value for the solubility rate is preferably 90% or higher. This will more reliably improve safety and the utilization efficiency of the raw material gas 26.

[0140] Furthermore, similar to the first embodiment, in addition to controlling the solubility rate, the consumption rate of combustible gases can also be controlled. This makes the improvement in the utilization efficiency of the raw material gas 26 more reliable.

[0141] Furthermore, in the second embodiment, as an example, hydroxide bacteria 21 were used as the culture medium, and the raw material gas 26 also contained hydrogen as a combustible gas, and oxygen and carbon dioxide as other components. The technology of the present invention is particularly effective in this combination of culture medium and raw material gas 26, as explained in the first embodiment.

[0142] Furthermore, in the culture apparatus 10 of the second embodiment, not all of the elements shown as a common structure may be provided; only a portion may be combined. Moreover, the structures of the second and first embodiments may be appropriately combined, as illustrated in the combination with solubility control.

[0143] 4. Third Implementation Method use Figure 22 The culture apparatus 310 of the third embodiment will be described. In the third embodiment, the culture apparatus 310 of the third embodiment will be described. Figures 1-9 An example of the common structure shown and Figures 10-16 The above-described structures, such as the first embodiment shown, are omitted and are marked with the same symbols.

[0144] like Figure 22As shown, the culture apparatus 310 of the third embodiment has a bubble generating device 128 and a culture medium supply channel 70. The bubble generating device 128 is used to mix the raw material gas 26 with the culture medium 18 before it is supplied to the culture tank 11. The culture medium supply channel 70 is disposed between the culture medium tank 13 and the culture tank 11, and supplies the culture medium 18 after the raw material gas 26 is mixed by the bubble generating device 128 to the culture tank 11. It is provided separately from the supply channel 15A that supplies the hydroxide bacteria 21 to the culture tank 11.

[0145] In the culture apparatus 310, for example, the culture medium tank 13 is equipped with a bubble generating device 128. The supply channel 12A for the raw material gas 26 is connected to the bubble generating device 128 in the culture medium tank 13. In the culture medium tank 13, the culture medium 18 mixed with the raw material gas 26 is supplied to the culture tank 11 through the culture medium supply channel 70. No bubble generating device such as the distributor 28 is provided in the culture tank 11. Hydroxyhydric bacteria 21 are supplied to the culture tank 11 through the supply channel 15A, which serves as the supply channel for the cultured organisms.

[0146] If the bubbles from the raw material gas 26 generated by the bubble generating device 128 come into contact with cultured organisms (microorganisms or cells) such as hydroxide bacteria 21, they will cause damage to the cultured organisms. Damage to the cultured organisms from the bubbles can sometimes lead to their death, resulting in a reduction in the number of cultured organisms in the culture medium 18. A reduction in the number of cultured organisms in the culture medium 18 will also decrease the consumption rate of flammable gases contained in the raw material gas 26, such as the hydrogen consumption rate. A decrease in the consumption rate of flammable gases will increase the amount of flammable gases contained in the mixed gas 31. This increases the risk of explosion and reduces safety.

[0147] The culture apparatus 310 of the third embodiment reduces the opportunity for bubbles of the raw material gas 26 to come into contact with the hydroxide bacteria 21 in the culture tank 11 by providing a culture solution supply channel 70, which is separate from the supply channel 15A for the hydroxide bacteria 21, to supply the culture solution 18 after the pre-mixed raw material gas 26. As a result, damage to the hydroxide bacteria 21 from the bubbles is reduced, and the reduction of hydroxide bacteria 21 in the culture solution 18 is suppressed. If the reduction of hydroxide bacteria 21 is suppressed, the consumption rate of flammable gases such as hydrogen consumption rate increases, and the amount of flammable gas contained in the mixed gas 31 decreases. Therefore, the risk of explosion decreases, thereby improving safety.

[0148] Furthermore, if the damage to the hydroxide bacteria 21 is reduced, the hydrogen consumption rate will increase, and the utilization efficiency and cultivation efficiency of the raw material gas 26 will also improve.

[0149] And, as Figure 22As shown, in the culture apparatus 310 of the third embodiment, in addition to the culture tank 11, the culture medium tank 13 is also equipped with a temperature regulator 47. This allows the temperature of the culture medium 18 in the culture tank 11 to be adjusted to be the same as the temperature in the culture medium tank 13.

[0150] In the culture apparatus 310, the culture medium 18 supplying the hydroxide bacteria 21 is located in the culture tank 11, and the culture medium 18 supplying the raw material gas 26 is located in the culture tank 13. The culture medium 18s of the culture tank 13 and the culture tank 11 are mixed through the culture medium supply channel 70. However, if there is a temperature difference between the two, the concentration of the raw material gas 26 may become uneven in the mixed culture medium 18 due to the temperature difference. If there is an uneven concentration of the raw material gas 26, the hydroxide bacteria 21 in areas with low concentrations of raw material gas 26 may die. By installing temperature regulators 47 in the culture tank 11 and the culture tank 13 respectively, the damage caused by the temperature difference in the culture medium 18 to the cultured organisms such as the hydroxide bacteria 21 can be reduced. As a result, the hydrogen consumption rate consumed by the hydroxide bacteria 21 is increased, and the amount of hydrogen contained in the mixed gas 31 is reduced, thus further improving safety. Similarly, the utilization efficiency of the raw material gas 26 and the culture efficiency are also improved.

[0151] Furthermore, the mixing of the raw material gas 26 and the culture medium 18 can be carried out only before being supplied to the culture tank 11; therefore, for example, a bubble generating device 128 can be installed in the culture medium supply channel 70. However, as Figure 22 As shown, compared to the case where a bubble generating device 128 is installed in the culture medium supply channel 70, there is more space to install the bubble generating device 128 in the culture medium tank 13, so it is easier to install the bubble generating device 128.

[0152] The bubble generating device 128 can be a distributor 28, a rotary shear type that generates bubbles through rotary shear force, or one of the aforementioned ejector or static mixer types. Compared to a distributor 28, these bubble generating devices have a higher output and can supply more raw material gas 26, thus offering excellent mass production applicability. Therefore, cultivation efficiency can be improved. On the other hand, the higher the output power of the bubble generating device 128, the greater the damage to the hydroxide bacteria 21 caused by the bubbles. In the third embodiment, the raw material gas 26 can be mixed with the culture medium 18 without considering the contact between the bubbles of the raw material gas 26 and the hydroxide bacteria 21. Therefore, a high-output bubble generating device 128, such as a rotary shear type, can be used.

[0153] Furthermore, the culture apparatus 310 in the third embodiment, like in the first embodiment, includes a culture medium circulation path 354. This culture medium circulation path 354 takes out a portion of the culture medium 18 from the culture tank 11, recovers a portion of the cultured object such as the hydroxide bacteria 21 from the taken-out culture medium 18, and returns the remaining culture medium 18 after recovery to the culture tank 11. The culture medium circulation path 354 in the third embodiment is configured to include a culture medium supply channel 70 connecting the culture medium tank 13 and the culture tank 11. The difference between the culture medium circulation path 354 in the third embodiment and the culture medium circulation path 54 in the first embodiment is that the culture medium is returned to the culture tank 11 via the culture medium tank 13. This culture medium circulation path 354 can be used for perfusion culture, in which culture medium 18 is perfused while culture is being performed. Even in the case of perfusion culture, the culture medium 18 after the recovery of the hydroxide bacteria 21 is returned to the culture medium tank 13, thus reducing the contact between the gas bubbles of the raw material gas 26 and the hydroxide bacteria 21. Therefore, the hydroxide bacteria 21 suffer less damage from the bubbles.

[0154] Furthermore, in the third embodiment, as an example, hydroxide bacteria 21 were used as the culture medium, and the raw material gas 26 also contained hydrogen as a flammable gas, and oxygen and carbon dioxide as other components. In this combination of culture medium and raw material gas 26, the technology of the present invention, which aims to improve safety, is particularly effective, similar to the first embodiment.

[0155] Furthermore, the hydroxide bacteria 21 consume hydrogen and carbon dioxide as energy and carbon sources, respectively. As described above, in the culture apparatus 310 of the third embodiment, since the raw material gas 26 and the culture medium 18 are mixed in the culture tank 13, the contact between the hydroxide bacteria 21 and the bubbles of the raw material gas 26 can be considered, and a high-output bubble generating device 128 can be used. Therefore, compared to the distributor 28 (see reference 128), the high-output bubble generating device 128 can be used. Figure 2 The device can adequately supply the raw material gas 26 to the culture medium 18 and dissolve it. Therefore, the culture apparatus 310 of the third embodiment can adequately provide nutrients to the hydroxide bacteria 21, which is advantageous in terms of culture efficiency.

[0156] Furthermore, in the third embodiment, as an example of a common structure, such as Figure 3 As shown, the raw material gas 26 can also supply hydrogen, oxygen, and carbon dioxide separately. Therefore, it is less likely to cause uneven concentration distribution of each component in the culture medium 18, and it is less likely to cause insufficient supply of raw material gas 26 to the hydroxide bacteria 21, thus minimizing damage to the hydroxide bacteria 21.

[0157] Furthermore, in the third embodiment, as an example of a common structure, such as Figure 7As shown, the bubble diameter d90 of the feed gas 26 can also be less than 1000 μm. As described above, by reducing the bubble diameter, the solubility can be further improved. This improves both safety and the utilization efficiency of the feed gas 26.

[0158] Furthermore, in the third embodiment, the composition ratio control shown in the first embodiment can also be performed. This further enhances safety.

[0159] Furthermore, in the culture apparatus 310 of the third embodiment, not all of the elements shown as a common structure may be provided; only a portion may be combined. Moreover, the structures of the third embodiment may be appropriately combined with those of the first and second embodiments, for example, with the solubility control and the longitudinally elongated culture tank 111.

[0160] 5. Fourth Implementation Method use Figure 23 and Figure 24 The culture apparatus 410 of the fourth embodiment will be described. In the fourth embodiment, the culture apparatus 410 of the fourth embodiment will be described. Figures 1-9 An example of the common structure shown and Figures 10-16 The above-described structures, such as the first embodiment shown, are omitted and are marked with the same symbols.

[0161] like Figure 23 As shown, the cultivation apparatus 410 of the fourth embodiment includes: a gas circulation path 439 for reusing the mixed gas 31 in space 11A as a raw material gas 26; and a fluid ejector 75 disposed on the gas circulation path 439 to impart a circulation pressure to the mixed gas 31, causing it to circulate. The fluid ejector 75 is an example of a pressure-imposing device that does not have a mechanically movable part and uses an externally input driving fluid to impart circulation pressure to the mixed gas 31. The pump 22 is a pressure-imposing device, but it has a mechanically movable part such as a rotating body, and the mixed gas 31, which is the object to which circulation pressure is imparted, comes into contact with the mechanically movable part. The pump 22 differs from the pressure-imposing device of this application that does not have a mechanically movable part in that it has a mechanically movable part.

[0162] The fluid ejector 75 has a first input port 75A for inputting mixed gas 31, a second input port 75B for inputting driving fluid, and an output port 75C for outputting mixed gas 31. A nozzle 75D for ejecting driving fluid is disposed deep within the second input port 75B.

[0163] Nozzle 75D has a tapered tip shape facing the nozzle to form the outlet. The tip of nozzle 75D is positioned at the confluence of the flow paths from the first input port 75A and the second input port 75B. When driving fluid is input to the second input port 75B from the outside, the flow velocity of the driving fluid increases due to the tapered tip shape of nozzle 75D as it passes through it, and it is ejected in this state. Because the driving fluid has a high flow velocity and low pressure, the mixed gas 31 input from the first input port 75A is attracted by the driving fluid and output from the output port 75C along with it. This imparts circulating pressure to the mixed gas 31.

[0164] As an example, the driving fluid is culture medium 18 taken from the culture tank 11. The culture medium 18, as the driving fluid, is pressurized by pump 22 and input into the fluid ejector 75. The culture medium 18 and the mixed gas 31 are output from the output port 75C of the fluid ejector 75 in a mixed state. The output port 75C is connected to a culture medium circulation path 454. The culture medium 18 and the mixed gas 31 are returned to the culture tank 11 through the culture medium circulation path 454. Thus, the mixed gas 31 is circulated. In this example, the culture medium circulation path 454 also serves as a gas circulation path 439.

[0165] Thus, the culture apparatus 410 of the fourth embodiment circulates the mixed gas 31 by providing a fluid ejector 75 in the gas circulation path 439 through which the mixed gas 31 circulates. The fluid ejector 75 is an example of a pressure-applying device without a mechanically movable part. Because it lacks a mechanically movable part, it does not generate heat due to friction and therefore does not become an ignition source such as high temperature, sparks, or static electricity. An ignition source is one of the three elements of an explosion. Therefore, in the culture apparatus 410, even when the mixed gas 31 is reused as the raw material gas 26, the risk of explosion is low, and safety is improved compared to the past.

[0166] Furthermore, in the culture apparatus 410, a pump 22 with a mechanically movable part is provided to pressurize the culture medium 18, which serves as the driving fluid. However, the pump 22 is not located in the gas circulation path 439 through which the mixed gas 31 circulates, so the mixed gas 31 does not come into contact with the pump 22, and the pump 22 will not become an ignition source that could cause an explosion of the mixed gas 31.

[0167] Thus, in the cultivation apparatus 410 of the fourth embodiment, devices that could potentially become ignition sources, such as the pump 22, are eliminated from the gas circulation path 439 through which the mixed gas 31 is circulated. Therefore, even if the composition ratio of the mixed gas 31 is within the explosive range, the safety is higher compared to the case where the pump 22 is arranged in the gas circulation path 439.

[0168] In the culture apparatus 410, the culture medium 18 is used as the driving fluid. The culture medium 18 is circulated in the same manner as the mixed gas 31, allowing for reuse during the culture process. Therefore, using the culture medium 18 as the driving fluid results in less waste compared to using a dedicated fluid that cannot be used as a driving fluid in the culture process. Furthermore, since the mixed gas 31 is dissolved in the culture medium 18 for reuse, using the culture medium 18 as the driving fluid is also advantageous from the viewpoint of preventing impurities from contaminating the raw material gas 26.

[0169] Furthermore, as described above, in the culture apparatus 410 of the fourth embodiment, even when the composition ratio of the mixed gas 31 is set within the explosive range, the safety is relatively high. Therefore, the supply amount of the raw material gas 26 can be determined based on the criterion of emphasizing the culture efficiency of the hydroxide bacteria 21, rather than from a safety perspective.

[0170] For example, in the culture apparatus 410, control can be performed as follows: during culture, the amount of raw material gas 26 consumed by the hydroxide bacteria 21 in the raw material gas 26 supplied to the culture tank 11 is measured, and raw material gas 26 exceeding the consumption amount is supplied. This control is easily performed in the culture apparatus 410 due to its high safety. The measurement of the consumption amount of raw material gas 26 can be performed in accordance with the method described in the first embodiment. Figure 12 The measurements are performed in the same order as described above. The raw material gas supply unit, including processor 17, calculates the amount of raw material gas 26 consumed that exceeds the measured consumption amount and determines the supply quantity. Through this control, the raw material gas 26 can be adequately supplied.

[0171] Specifically, the supply amount of raw material gas 26 to the culture tank 11 via the raw material gas supply unit and gas circulation path 39 can be 2 to 15 times the consumption of raw material gas 26. That is, the total supply amount of raw material gas 26 to the culture tank 11 is controlled to be 2 to 15 times the consumption of raw material gas 26 within the culture tank 11. If the total supply amount of raw material gas 26 is set to this level, a sufficient amount of raw material gas 26 required by the hydroxide bacteria 21 can be supplied without causing a shortage of raw material gas 26. Furthermore, if this sufficient amount of raw material gas 26 is supplied, the uneven concentration of raw material gas 26 within the culture tank 11 will also be reduced. This improves culture efficiency.

[0172] Furthermore, the culture apparatus 410 of the fourth embodiment can, of course, be appropriately combined with the structures of the above-described embodiments. For example, it is also possible to perform... Figure 11The composition ratio control shown in the figure maintains the composition ratio of the mixed gas 31 within the target value of the explosion range. In the fourth embodiment, since the ignition source is eliminated from the gas circulation path 439, the safety is high even if the composition ratio of the mixed gas 31 is within the explosion range, but the safety is further improved by controlling the composition ratio of the mixed gas 31.

[0173] And, as Figure 23 As shown, a structure can also be adopted in which the mixed gas outlet 34 of the gas circulation path 439 is positioned at a location capable of taking in the foam layer 18B. Thus, as shown in an example of a common structure, the adverse effects of the foam layer 18B can be reduced.

[0174] Furthermore, in the fourth embodiment, as an example, hydroxide bacteria 21 were used as the microorganism to be cultured, and the raw material gas 26 contained hydrogen as a flammable gas and oxygen and carbon dioxide as other components. The technology of the present invention is particularly effective in this combination of culture medium and raw material gas 26. As described above, the raw material gas 26 contains oxygen as an oxidizing gas in addition to hydrogen as a flammable gas. Therefore, measures to suppress explosions are very important for safety, and the technology of the present invention, which can further improve safety, is particularly effective.

[0175] In this example, the output port 75C of the fluid ejector 75 is connected to the culture tank 11 via a pipe through the culture medium circulation path 454, but the output port 75C can also be directly connected to the culture tank 11 without pipe.

[0176] In this example, a fluid ejector 75 is used as a pressure-applying device without a mechanically movable part. Many existing products are readily available for use with fluid ejectors 75. Of course, a rotary shear pressure-applying device can be used instead of the fluid ejector 75, for example, as a pressure-applying device without a mechanically movable part. The rotary shear pressure-applying device generates a high-speed rotating flow by rotating the driving fluid, and uses the pressure of the high-speed rotating flow to apply circulating pressure to the mixed gas 31. Furthermore, as an example, ENVIRO VISION CO.,LTD.'s bubble-generating device "YJ nozzle" can also be used as a pressure-applying device. The "YJ nozzle" can also be used as a bubble-generating device, but... Figure 23 Similarly, the fluid ejector 75 shown can also be used as a pressure-applying device that applies pressure to a fluid by utilizing pressure changes within the flow path.

[0177] Furthermore, in Figure 23 In the example, the process of returning the culture medium 18 and the mixed gas 31 to the culture tank 11 is described, but as... Figure 24As shown, the culture medium 18 and the mixed gas 31 can also be returned to the culture tank 11 after separation.

[0178] In this case, after the culture medium 18 and mixed gas 31 are output from the output port 75C of the fluid ejector 75 in a mixed state, the culture medium 18 and mixed gas 31 are separated by the gas separation mechanism 61. The separated culture medium 18 is then returned to the culture tank 11 via the culture medium circulation path 454. On the other hand, the separated gas is returned to the culture tank 11 via the gas reuse path 62. The gas reuse path 62 is, for example, equipped with a fluid ejector 76 that applies circulating pressure to the separated gas. As an example, the fluid ejector 76 uses carbon dioxide as the driving fluid. Since carbon dioxide is a component of the separated gas, impurities will not mix into the separated gas. The separated gas is returned to the culture tank 11 via the fluid ejector 76.

[0179] In the above embodiments, hydroxide bacteria 21 were described as an example of microorganisms, but the technology of the present invention can also be applied to microorganisms or cells other than hydroxide bacteria 21. For example, acetic acid-producing bacteria such as Clostridium ethanoliferum and methanogenic bacteria such as Methylcoccus capsulatum can also be used as microorganisms. In the case of acetic acid-producing bacteria, the components of the raw material gas 26 are hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2), which are combustible gases. In the case of methanogenic bacteria, the components of the raw material gas 26 are methane (CH4), which is a combustible gas, and air. Furthermore, a cell refers to the morphological and / or functional unit constituting a living organism. The living organism from which the cell originates is not particularly limited and can be an animal or a plant. The cell can be a passaged cell or a genetically recombinant cell, and may also include artificial cells. For example, CHO cells (Chinese hamster ovary cells), HEK293 cells (Human Embryonic Kidney cells 293), and Sf9 cells (Spodoptera frugiperda cells 9) can be cited.

[0180] (Regarding the notes) Furthermore, based on the descriptions of the first to fourth embodiments above, the invention described in the following appendices can be mastered.

[0181] (Note 1) [Note 1] A culture apparatus for culturing microorganisms or cells that use a feed gas containing combustible gas for proliferation or the production of organic matter, the culture apparatus comprising: A culture tank is a medium used to culture microorganisms or cells. The raw material gas supply unit supplies raw material gas to the culture tank; The composition ratio control mechanism measures the composition ratio of the mixed gas in the space above the liquid surface of the culture medium in the culture tank, and supplies adjustment gas into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside the preset explosion range. A gas circulation path is used to reuse the mixed gas in the space as a feed gas; and The solubility control mechanism measures the proportion of flammable gases dissolved in the culture liquid from the flammable gases contained in the raw material gas supplied to the culture tank through the gas circulation path or the raw material gas supply unit during cultivation, which is the flammable gas solubility rate, and maintains the measured flammable gas solubility rate above the preset target value. [Note 1, item 2] According to the culture apparatus described in Appendix 1, wherein, The target value for the solubility of flammable gases is above 90%. [Note 1, item 3] The culture apparatus according to Appendix 1 or Appendix 2, wherein, The solubility control mechanism also performs the following processing: During cultivation, the proportion of combustible gases consumed by microorganisms or cells in the raw material gas supplied to the culture tank through the gas circulation path and the raw material gas supply unit is measured, which is the combustible gas consumption rate. The measured combustible gas consumption rate is maintained above 90% by controlling the solubility of the combustible gases. [Note 1, item 4] The culture apparatus according to any one of the first appendix items 1 to 3, wherein, Regarding the bubble diameter of the raw material gas generated in the culture medium, d90 is less than 1000 μm. [Note 1, item 5] The culture apparatus according to any one of the first appendix items 1 to 4, wherein, The culture medium contains a surface tension reducer. [Note 1, item 6] The culture apparatus according to any one of the first appendix items 1 to 5, wherein, The surface tension of the culture medium is below 65 mN / m. [Note 1, item 7] The culture apparatus according to any one of the first appendix items 1 to 6, wherein, The microorganism is hydroxide bacteria. The feed gas contains hydrogen as a combustible gas, and oxygen and carbon dioxide as other components. The gas used for adjustment is carbon dioxide. [Note 1, item 8] The culture apparatus according to any one of the first appendix 1 to 7 comprises: The first component separation mechanism separates specific components from the mixed gas taken from the culture tank; or the second component separation mechanism separates specific components from the separated gas separated from the culture medium taken from the culture tank. [Note 1, item 9] The culture apparatus according to any one of the first appendix items 1 to 8, wherein, In the gas circulation path, the gas outlet for taking out the mixed gas from the culture tank is positioned at a location that can take in the foam layer present on the liquid surface in the culture tank. [Note 1, item 10] The culture apparatus according to any one of the first appendix 1 to 9 comprises: The culture medium recovery mechanism recovers a portion of the culture medium, including the organic matter produced, from the culture medium taken from the culture tank, which is called the recovery liquid. A recovery liquid tank for storing recovery liquid containing organic matter; and The concentration reduction mechanism reduces the concentration of dissolved flammable gases in the recovered liquid stored in the recovered liquid tank to less than 1 / 10 of the concentration of dissolved flammable gases in the culture liquid in the culture tank. [Note 11] The culture apparatus according to any one of Appendix 1 to Appendix 10 includes an explosion suppression mechanism. The explosion suppression mechanism suppresses explosions within the gas reuse path used for reusing gases separated from the culture medium. [Note 1, item 12] A method for controlling a culture apparatus comprising a culture tank and a raw material gas supply unit for culturing microorganisms or cells, wherein the culture tank contains a culture medium, the culture medium culturing microorganisms or cells for proliferation or the production of organic matter using a raw material gas containing a combustible gas, and the raw material gas supply unit supplying a raw material gas containing a combustible gas to the culture tank. In the control method of this culture device, the composition ratio of the mixed gas in the space above the liquid surface of the culture medium in the culture tank is measured, and an adjusting gas is supplied into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a preset explosion range. During cultivation, the proportion of combustible gases dissolved in the culture liquid in the raw gas supplied to the cultivation tank through a gas circulation path or raw gas supply unit for reuse of the mixed gas in the space as raw gas is measured, which is the combustible gas solubility rate, and the measured combustible gas solubility rate is maintained at a preset target value.

[0182] (Note 2) [Note 2, item 1] A culture apparatus for culturing microorganisms or cells that use a feed gas containing combustible gas for proliferation or the production of organic matter, the culture apparatus comprising: A culture tank is a medium used to culture microorganisms or cells. The raw material gas supply unit supplies raw material gas to the culture tank; and The composition ratio control mechanism measures the composition ratio of the mixed gas in the space above the surface of the culture medium within the culture tank, and supplies adjusting gas into the space according to the measured composition ratio, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a preset explosion range. When the equivalent circle diameter of the section orthogonal to the height direction of the culture tank is set as DAm, and the maximum height of the liquid surface is set as H, the size of the culture tank satisfies the condition H / DAm≥2. [Note 2] According to the culture apparatus described in Appendix 2, paragraph 1, wherein, The culture tank is a cylindrical shape with a bottom. [Note 2, item 3] The culture apparatus according to Appendix 2, paragraph 1 or 2, wherein, The condition is H / DAm≥13. [Note 2, item 4] The culture apparatus according to any one of Appendix 1 to Appendix 3, wherein, Regarding the bubble diameter of the raw material gas generated in the culture medium, d90 is less than 1000 μm. [Note 2, item 5] The culture apparatus according to any one of Appendix 1 to Appendix 4 of the second edition has a temperature regulator for adjusting the temperature of the culture medium, at least a portion of which is disposed within the culture tank. [Note 2, item 6] According to the culture apparatus described in Appendix 2, paragraph 5, wherein, The overall length of the temperature regulator in the height direction of the culture tank is more than 30% of the maximum height of the liquid surface. [Note 2, item 7] The culture apparatus according to Appendix 5 or Appendix 6, wherein, There are multiple temperature regulators, which are configured at different positions along the height of the culture tank. [Note 2, item 8] The culture apparatus according to any one of Appendix 5 to Appendix 7 of the second paragraph includes a stirring mechanism. The stirring mechanism has multiple stirring sections for stirring the culture medium. Multiple stirring units are arranged at different positions along the height of the culture tank. [Note 2, item 9] According to the culture apparatus described in Appendix 2, paragraph 8, wherein, With multiple temperature regulators and multiple stirring sections Multiple pairs, consisting of at least one temperature regulator and at least one stirring unit, are arranged at different positions in the height direction of the culture tank. [Note 2, item 10] The culture apparatus according to any one of Appendix 1 to Appendix 9 of the second appendix comprises: A gas circulation path is used to reuse the mixed gas in the space as a feed gas; and The solubility control mechanism measures the proportion of flammable gases dissolved in the culture liquid from the flammable gases contained in the raw material gas supplied to the culture tank through the gas circulation path and the raw material gas supply unit during cultivation, which is the flammable gas solubility rate, and maintains the measured flammable gas solubility rate at a preset target value. [Note 2, item 11] According to the culture apparatus described in Appendix 2, paragraph 10, wherein, The target value for the solubility of flammable gases is above 90%. [Note 2, item 12] The culture apparatus according to Appendix 2, paragraph 10 or 2, paragraph 11, wherein, The solubility control mechanism also performs the following processing: During cultivation, the combustible gas consumption rate of the combustible gas consumed by microorganisms or cells in the combustible gas contained in the raw material gas supplied to the culture tank through the gas circulation path or the raw material gas supply unit is measured, and the measured combustible gas consumption rate is maintained above 90% by controlling the solubility rate of the combustible gas. [Note 2, item 13] The culture apparatus according to any one of Appendix 1 to Appendix 12, wherein, The microorganism is hydroxide bacteria. The feed gas contains hydrogen as a combustible gas, and oxygen and carbon dioxide as other components. The gas used for adjustment is carbon dioxide. [Note 2, item 14] The culture apparatus according to any one of Appendix 1 to Appendix 13 of the second paragraph comprises: The first component separation mechanism separates specific components from the mixed gas taken from the culture tank; or the second component separation mechanism separates specific components from the separated gas separated from the culture medium taken from the culture tank. [Note 2, item 15] The culture apparatus according to any one of Appendix 2, Items 11 to 14, comprises: A gas circulation path is used to reuse the mixed gas in the space as a feed gas; and The solubility control mechanism measures the proportion of flammable gases dissolved in the culture liquid from the flammable gases contained in the raw material gas supplied to the culture tank through the gas circulation path and the raw material gas supply unit during cultivation; this is the flammable gas solubility rate. The measured flammable gas solubility rate is then maintained at a preset target value. In the gas circulation path, the gas outlet for taking out the mixed gas from the culture tank is positioned at a location that can take in the foam layer present on the liquid surface in the culture tank. [Note 2, item 16] The culture apparatus according to any one of Appendix 1 to Appendix 15 of the second appendix comprises: The culture medium recovery mechanism recovers a portion of the culture medium, including the organic matter produced, from the culture medium taken from the culture tank, which is called the recovery liquid. A recovery liquid tank for storing recovery liquid containing organic matter; and The concentration reduction mechanism reduces the concentration of dissolved flammable gases in the recovered liquid stored in the recovered liquid tank to less than 1 / 10 of the concentration of dissolved flammable gases in the culture liquid in the culture tank. [Note 2, item 17] The culture apparatus according to any one of Appendix 1 to Appendix 16 of the second paragraph includes an explosion suppression mechanism. The explosion suppression mechanism suppresses explosions within the gas reuse path used for reusing gases separated from the culture medium. [Note 2, item 18] A method for controlling a culture apparatus comprising a culture tank and a raw material gas supply unit for culturing microorganisms or cells, wherein the culture tank contains a culture medium, the culture medium culturing microorganisms or cells for proliferation or the production of organic matter using a raw material gas containing a combustible gas, and the raw material gas supply unit supplying a raw material gas containing a combustible gas to the culture tank. In the control method of this culture device, when the equivalent circle diameter of the section orthogonal to the height direction of the culture tank is set as DAm, and the maximum height of the liquid surface is set as H, the dimensions of the culture tank satisfy the condition H / DAm≥2. The composition ratio of the mixed gas in the space above the liquid surface of the culture medium in the culture tank is measured, and an adjustment gas is supplied into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside the preset explosion range.

[0183] (Note 3) [Note 3, item 1] A culture apparatus for culturing microorganisms or cells that use a feed gas containing combustible gas for proliferation or the production of organic matter, the culture apparatus comprising: A culture tank is a medium used to culture microorganisms or cells. Culture medium tank, used to store the culture medium supplied to the culture tank; The culture medium supply channel supplies microorganisms or cells to the culture tank; Raw material gas tank, used to store raw material gases; A bubble generating device is used to mix the raw material gas with the culture liquid before it is supplied to the culture tank; and The culture medium supply channel is located between the culture medium tank and the culture tank. It supplies the culture medium, after the raw material gas is mixed by the bubble generating device, to the culture tank and is set separately from the culture object supply channel. [Note 3, item 2] According to the culture apparatus described in Appendix 3, paragraph 1, wherein, The culture tank and culture medium tank are each equipped with a temperature regulator to adjust the temperature of the culture medium. [Note 3] The culture apparatus according to Appendix 3, paragraph 1 or 3, paragraph 2, wherein, The bubble generating device is located in the culture medium tank. [Note 3, item 4] The culture apparatus according to any one of Appendix 3 1 to Appendix 3 3, wherein, The bubble generating device uses rotational shear force to generate bubbles. [Note 3, item 5] The culture apparatus according to any one of Appendix 3 1 to Appendix 3 4 includes a culture medium circulation path. The culture medium circulation path involves taking out a portion of the culture medium from the culture tank, recovering a portion of the microorganisms or cells from the taken-out culture medium, and returning the remaining culture medium after recovery to the culture tank via a culture medium container. [Note 3, item 6] The culture apparatus according to any one of Appendix 3 1 to Appendix 3 5, wherein, The microorganism is hydroxide bacteria. The raw material gas contains hydrogen as a combustible gas, and oxygen and carbon dioxide as other components. [Note 3, item 7] According to the culture apparatus described in Appendix 3, paragraph 6, wherein... The components of the raw gas, namely hydrogen, oxygen and carbon dioxide, are supplied separately. [Note 3, item 8] The culture apparatus according to any one of Appendix 3, paragraphs 1 to 7, wherein, Regarding the bubble diameter of the raw material gas generated in the culture medium, d90 is less than 1000 μm. [Note 3, item 9] The culture apparatus according to any one of Appendix 3, Items 1 to 8, comprises a composition ratio control mechanism. The composition ratio control mechanism measures the composition ratio of the mixed gas in the space above the liquid surface of the culture medium in the culture tank, and supplies adjustment gas into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside the preset explosion range. [Note 3, item 10] The culture apparatus according to any one of Appendix 3, Items 1 to 9, comprises: The first component separation mechanism separates specific components from the mixed gas taken from the culture tank; or the second component separation mechanism separates specific components from the separated gas separated from the culture medium taken from the culture tank. [Note 3, item 11] The culture apparatus according to any one of Appendix 3, paragraphs 1 to 10, wherein, In the gas circulation path that circulates the mixed gas taken from the culture tank, the mixed gas outlet for taking out the mixed gas from the culture tank is positioned at a location that can take in the foam layer on the surface of the culture liquid present in the culture tank. [Note 3, item 12] The culture apparatus according to any one of Appendix 1 to Appendix 11 of the third paragraph comprises: The culture medium recovery mechanism recovers a portion of the culture medium, including the organic matter produced, from the culture medium taken from the culture tank, which is called the recovery liquid. A recovery liquid tank for storing recovery liquid containing organic matter; and The concentration reduction mechanism reduces the concentration of dissolved flammable gases in the recovered liquid stored in the recovered liquid tank to less than 1 / 10 of the concentration of dissolved flammable gases in the culture liquid in the culture tank. [Note 3, item 13] The culture apparatus according to any one of Appendix 3, Items 1 to 12, comprises an explosion suppression mechanism. The explosion suppression mechanism suppresses explosions within the gas reuse path used for reusing gases separated from the culture medium.

[0184] (Note 4) [Note 4, item 1] A culture apparatus for culturing microorganisms or cells that use a feed gas containing combustible gas for proliferation or the production of organic matter, the culture apparatus comprising: A culture tank is a medium used to culture microorganisms or cells. The raw material gas supply unit supplies raw material gas to the culture tank; A gas circulation path is used to reuse the mixed gas in the space above the liquid surface of the culture medium within the culture tank as a feed gas; and A pressure-applying device, positioned along the gas circulation path, applies a circulating pressure to the gas mixture to ensure its circulation. The pressure-imposing device has no mechanical moving parts and uses the input driving fluid to impart circulating pressure to the mixed gas. [Note 4, item 2] According to the culture apparatus described in Appendix 4, paragraph 1, wherein, The pressure-applying device is a fluid ejector. [Note 4, item 3] According to the culture apparatus described in Appendix 4, paragraph 2, wherein, The driving fluid input to the fluid ejector is the culture medium taken from the culture tank. [Note 4] The culture apparatus according to any one of Appendix 4, 1 to 3, wherein, During cultivation, the amount of raw material gas consumed by microorganisms or cells in the raw material gas supplied to the culture tank is measured. The raw material gas supply department supplies raw material gas exceeding the consumption amount. [Note 4, item 5] The culture apparatus according to any one of Appendix 4, paragraphs 1 to 4, wherein, The amount of raw material gas supplied to the culture tank through the raw material gas supply unit and gas circulation path is 2 to 15 times the amount of raw material gas consumed. [Note 4, item 6] The culture apparatus according to any one of Appendix 4, Items 1 to 5, comprises a composition ratio control mechanism. The composition ratio control mechanism measures the composition ratio of the mixed gas in the space above the liquid surface of the culture medium in the culture tank, and supplies adjustment gas into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside the preset explosion range. [Note 4, item 7] The culture apparatus according to any one of Appendix 4, paragraphs 1 to 6, wherein, In the gas circulation path, the gas outlet for taking out the mixed gas from the culture tank is positioned at a location that can take in the foam layer present on the liquid surface in the culture tank. [Note 4, item 8] The culture apparatus according to any one of Appendix 4, paragraphs 1 to 7, wherein, The microorganism is hydroxide bacteria. The raw material gas contains hydrogen as a combustible gas, and oxygen and carbon dioxide as other components. [Note 4, item 9] The culture apparatus according to any one of Appendix 4, Items 1 to 8, comprises: The first component separation mechanism separates specific components from the mixed gas taken from the culture tank; or the second component separation mechanism separates specific components from the separated gas separated from the culture medium taken from the culture tank. [Note 4, item 10] The culture apparatus according to any one of Appendix 4, Items 1 to 9, comprises: The culture medium recovery mechanism recovers a portion of the culture medium, including the organic matter produced, from the culture medium taken from the culture tank, which is called the recovery liquid. A recovery liquid tank for storing recovery liquid containing organic matter; and The concentration reduction mechanism reduces the concentration of dissolved flammable gases in the recovered liquid stored in the recovered liquid tank to less than 1 / 10 of the concentration of dissolved flammable gases in the culture liquid in the culture tank. [Note 4, item 11] The culture apparatus according to any one of Appendix 4, Items 1 to 10, comprises an explosion suppression mechanism. The explosion suppression mechanism suppresses explosions within the gas reuse path used for reusing gases separated from the culture medium.

[0185] The aforementioned processors include general-purpose processors such as CPUs, which execute software (programs) to perform various processing functions. In addition, they also include programmable logic devices (PLDs) such as FPGAs (Field Programmable Gate Arrays), which are processors whose circuit structure can be changed after manufacturing, and special-purpose circuits such as ASICs (Application Specific Integrated Circuits), which are processors with circuit structures specifically designed to perform specific processes.

[0186] Furthermore, more specifically, the hardware structure of these various processors can be a circuit composed of combined semiconductor elements and other circuitry.

[0187] The descriptions and illustrations shown above are detailed explanations of the parts related to the technology of this invention, and are merely one example of the technology of this invention. For example, the descriptions related to the above-described structure, function, effect, and effect are examples of the structure, function, effect, and effect of the parts related to the technology of this invention. Therefore, it is self-evident that unnecessary parts may be deleted, new elements may be added, or substitutions may be made to the descriptions and illustrations shown above without departing from the spirit of this invention. Furthermore, to avoid complexity and to facilitate understanding of the parts related to the technology of this invention, descriptions related to technical common sense that do not require special explanation in aspects enabling the implementation of this invention have been omitted from the descriptions and illustrations shown above.

[0188] The entire contents of the invention described in Japanese Patent Application No. 2023-125057, filed on July 31, 2023, are incorporated herein by reference. Furthermore, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as those specifically and separately described and incorporated herein by reference.

Claims

1. A culture apparatus for culturing microorganisms or cells that use a feed gas containing combustible gas for proliferation or the production of organic matter, said culture apparatus comprising: A culture tank, containing a culture medium for culturing the microorganisms or the cells; The raw material gas supply unit supplies the raw material gas to the culture tank; and The composition ratio control mechanism measures the composition ratio of the mixed gas in the space above the surface of the culture medium within the culture tank, and supplies adjusting gas into the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a preset explosion range. When the equivalent circle diameter of the section orthogonal to the height direction of the culture tank is set as DAm and the maximum height of the liquid surface is set as H, the size of the culture tank satisfies the condition H / DAm≥2.

2. The culture apparatus according to claim 1, wherein, The culture tank is a cylindrical shape with a bottom.

3. The culture apparatus according to claim 1, wherein, The condition is H / DAm≥13.

4. The culture apparatus according to claim 1, wherein, Regarding the bubble diameter of the raw material gas generated in the culture medium, d90 is less than 1000 μm.

5. The culture apparatus according to claim 1, wherein a temperature regulator is provided for adjusting the temperature of the culture medium, at least a portion of the temperature regulator being disposed within the culture tank.

6. The culture apparatus according to claim 5, wherein, The temperature regulator has a length that is at least 30% of the maximum height of the liquid level in the height direction of the culture tank.

7. The culture apparatus according to claim 5, wherein, There are multiple temperature regulators, and each temperature regulator is configured at a different position in the height direction of the culture tank.

8. The culture apparatus according to claim 5, further comprising a stirring mechanism. The stirring mechanism has multiple stirring sections for stirring the culture medium. Multiple stirring units are arranged at different positions along the height of the culture tank.

9. The culture apparatus according to claim 8, wherein, In the case of having multiple temperature regulators and multiple stirring sections Multiple pairs, consisting of at least one of the temperature regulators and at least one of the stirring units, are arranged at different positions in the height direction of the culture tank.

10. The culture apparatus according to claim 1, comprising: A gas circulation path for reusing the mixed gas within the space as the raw material gas; and The solubility control mechanism, during cultivation, measures the proportion of flammable gases dissolved in the culture solution from the flammable gases contained in the raw material gas supplied to the culture tank through the gas circulation path and the raw material gas supply unit, which is the flammable gas solubility rate, and maintains the measured flammable gas solubility rate at a preset target value.

11. The culture apparatus according to claim 10, wherein, The target value for the solubility of the combustible gas is above 90%.

12. The culture apparatus according to claim 10, wherein, The solubility control mechanism also performs the following processing: During cultivation, the combustible gas consumption rate of the combustible gas consumed by the microorganisms or cells in the combustible gas contained in the raw material gas supplied to the culture tank through the gas circulation path or the raw material gas supply unit is measured, and the measured combustible gas consumption rate is maintained above 90% by controlling the solubility rate of the combustible gas.

13. The culture apparatus according to claim 1, wherein, The microorganism is an hydroxide bacterium. The raw material gas contains hydrogen as the combustible gas, and oxygen and carbon dioxide as other components. The gas used for adjustment is carbon dioxide.

14. The culture apparatus according to claim 1, comprising: A first component separation mechanism separates specific components from the mixed gas taken from the culture tank; or a second component separation mechanism separates specific components from the separated gas separated from the culture medium taken from the culture tank.

15. The culture apparatus according to claim 10, wherein, On the gas circulation path, the gas outlet for taking out the mixed gas from the culture tank is positioned at a location that can take in the foam layer present on the surface of the liquid in the culture tank.

16. The culture apparatus according to claim 1, comprising: A culture medium recovery mechanism recovers a portion of the culture medium containing the generated organic matter from the culture medium removed from the culture tank, namely, the recovery liquid; A recovery liquid tank for storing a recovery liquid containing the organic matter; and The concentration reduction mechanism reduces the concentration of dissolved flammable gases in the recovered liquid stored in the recovered liquid tank to less than 1 / 10 of the concentration of dissolved flammable gases in the culture liquid in the culture tank.

17. The cultivation apparatus according to claim 1, further comprising an explosion suppression mechanism. The explosion suppression mechanism suppresses explosions within the gas reuse path for reusing gases separated from the culture medium.

18. A method for controlling a culture apparatus comprising a culture tank and a raw material gas supply unit for culturing microorganisms or cells, wherein the culture tank contains a culture medium, the culture medium culturing microorganisms or cells for proliferation or organic matter production using a raw material gas containing a combustible gas, and the raw material gas supply unit supplying a raw material gas containing a combustible gas to the culture tank. In the control method of the culture device, when the equivalent circle diameter of the cross-section orthogonal to the height direction of the culture tank is set as DAm and the maximum height of the liquid surface is set as H, the dimensions of the culture tank satisfy the condition H / DAm≥2. The composition ratio of the mixed gas in the space above the surface of the culture medium in the culture tank is determined, and an adjustment gas is supplied to the space according to the measured composition ratio of the mixed gas, thereby maintaining the composition ratio of the mixed gas in the space at a target value outside a predetermined explosion range.

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