Culture device and method for controlling culture device

Abstract

A culture device for culturing microorganisms or cells using a starting material gas including a combustible gas for proliferation or generation of an organic substance, the culture device being provided with: a culture tank for accommodating a culture solution for culturing the microorganisms or cells; a raw material gas supply unit for supplying a raw material gas to the culture tank; a composition ratio measurement unit 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 a composition ratio control means for maintaining the composition ratio of the mixed gas in the space at a target value outside a preset explosion range by supplying an adjustment gas into the space on the basis of the measured composition ratio of the mixed gas.

Description

Technical Field

[0001] The technology of the present invention relates to a culture device and a control method of the culture device. Background Art

[0002] With the purpose of suppressing the emission of greenhouse gases, research on the de-petroleumization of raw materials is being actively carried out worldwide. As part of this research, in the field of product manufacturing such as chemical products and biological products, a technology that uses carbon sources other than petroleum as raw materials has been developed. For example, it is known that there are microorganisms that use carbon sources other than petroleum as raw materials for proliferation or the production of organic substances. As an example of such a microorganism, there are hydrogen oxidizing bacteria. Hydrogen oxidizing bacteria proliferate by taking in gases containing carbon dioxide, hydrogen and oxygen as raw materials, and organic substances such as alcohols and amino acids are efficiently produced by changing the genes of hydrogen oxidizing bacteria. Hydrogen oxidizing bacteria is a general term for chemical synthetic bacteria that converts the carbon contained in carbon dioxide into organic substances and takes them into bacteria using the energy generated by the oxidation of hydrogen. In hydrogen oxidizing bacteria, carbon dioxide becomes a raw material for proliferation or the production of organic substances, and therefore it is also of interest from the viewpoint that carbon dioxide discharged as greenhouse gases can be effectively utilized.

[0003] A culture device for culturing hydrogen oxidizing bacteria is disclosed in Japanese Patent Publication No. 51-038480 and Japanese Patent No. 2564008. The culture device has a culture tank for containing a culture solution. A raw gas containing carbon dioxide, hydrogen and oxygen is supplied to the culture tank, and a part of the carbon dioxide, hydrogen and oxygen contained in the raw gas is dissolved in the culture solution and consumed in the proliferation of hydrogen oxidizing bacteria or the production of organic matter. The remaining raw gas is released into the space above the liquid surface of the culture solution in the culture tank and is discharged outside the culture tank. A mixed gas containing hydrogen and oxygen as flammable gases has the risk of explosion depending on the composition ratio, so a technology for suppressing explosion is disclosed in Japanese Patent Publication No. 51-038480 and Japanese Patent No. 2564008.

[0004] In Japanese Patent Application Laid-Open No. 51-038480, a hydrogen tank for containing hydrogen and an oxygen tank for containing oxygen are provided separately from a culture tank for containing culture solution, and the culture solution is circulated among the three tanks, the culture tank, the hydrogen tank and the oxygen tank. In Japanese Patent Application Laid-Open No. 51-038480, since the hydrogen tank and the oxygen tank exist independently, the generation of the mixed gas containing hydrogen and oxygen itself, which may cause an explosion, is suppressed.

[0005] In Japanese Patent No. 2564008, the supply of oxygen contained in the raw material gas is independently controlled, the dissolved oxygen concentration in the culture solution is measured, and the oxygen supply to the culture tank is limited based on the measured dissolved oxygen concentration. Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] In the method described in Japanese Patent Publication No. 51-038480, on the circulation path of the culture solution, the culture solution passes through a hydrogen tank rich in hydrogen and an oxygen tank rich in oxygen. In order to efficiently cultivate microorganisms such as hydrogen oxidizing bacteria, it is preferred that the concentrations of hydrogen and oxygen in the culture solution are always maintained at appropriate concentrations. However, in the hydrogen tank and the oxygen tank, hydrogen or oxygen is rich, so during the period when the culture solution passes through the hydrogen tank and the oxygen tank, it is impossible to maintain an appropriate concentration. Therefore, in Japanese Patent Publication No. 51-038480, there is concern from the viewpoint of the culture efficiency of microorganisms.

[0008] In the method described in Japanese Patent No. 2564008, the dissolved oxygen concentration in the culture solution is measured, but no measures are taken for the composition ratio of the mixed gas released from the culture solution. Since the composition ratio of the mixed gas that causes the explosion is not controlled, Japanese Patent No. 2564008 has concerns from the perspective of safety in preventing the explosion. In addition, in Japanese Patent No. 2564008, the dissolved oxygen concentration in the culture solution is controlled by limiting the supply of oxygen from the perspective of preventing the explosion. Therefore, sometimes the supply of oxygen required for the proliferation of microorganisms or the production of organic matter is reduced, which is a concern from the perspective of the culture efficiency of microorganisms.

[0009] The technology of the present invention provides a culture device and a control method of the culture device that can improve the culture efficiency and safety compared with the past when culturing microorganisms or cells that use a raw material gas containing a combustible gas for growth or production of organic substances.

[0010] Means for solving technical problems

[0011] In order to achieve the above-mentioned purpose, the culture device of the present invention cultures microorganisms or cells that utilize raw gas containing combustible gas for proliferation or production of organic matter, and the culture device comprises: a culture tank that contains culture liquid for culturing microorganisms or cells; a raw gas supply unit that supplies raw gas to the culture tank; a composition ratio measuring unit that measures the composition ratio of the mixed gas in the space above the liquid surface of the culture liquid in the culture tank; and a composition ratio control mechanism that maintains the composition ratio of the mixed gas in the space at a target value outside a preset explosion range by supplying an adjusting gas into the space according to the measured composition ratio of the mixed gas.

[0012] The adjusting gas is preferably an inert gas.

[0013] Preferably, the target value outside the explosion range is set to an oxygen concentration of less than 5% or a hydrogen concentration of less than 4%, and the composition ratio control means controls the composition ratio based on the target value.

[0014] Preferably, the target values ​​outside the explosion range are: an oxygen concentration of 5% or more and 9% or less, and a water vapor concentration of 7% or more, and the composition ratio control means controls the composition ratio based on the target values.

[0015] It is preferable to provide a temperature control mechanism for controlling the temperature of the culture solution.

[0016] Preferably, the temperature control mechanism controls the temperature of the culture solution to 40° C. or higher.

[0017] It is preferable to have a spraying mechanism for spraying a liquid containing water in the space.

[0018] Preferably, the liquid is an aqueous solution containing at least a part of the components of the culture solution.

[0019] It is preferred to have a foam layer forming part for forming a foam layer on the liquid surface of the culture liquid.

[0020] It is preferable to have a circulation path for recycling the mixed gas in the space as a raw material gas.

[0021] Preferably the combustible gas is hydrogen.

[0022] Preferably, the raw material gas contains hydrogen, oxygen and carbon dioxide.

[0023] The adjusting gas is preferably carbon dioxide.

[0024] Preferably the microorganism is a hydrogen oxidizing bacterium.

[0025] Preferably, it comprises: a pressure measuring unit for measuring the pressure in the space; and a pressure control mechanism for controlling the pressure by adjusting at least one of the supply amount of the raw material gas, the discharge amount of the mixed gas, and the supply amount of the adjustment gas according to the measured pressure.

[0026] Preferably, the culture medium comprises: a dissolved gas concentration measuring unit for measuring the dissolved gas concentration of a raw material gas dissolved in the culture solution; and a raw material gas control mechanism for controlling the supply amount of the raw material gas according to the dissolved gas concentration.

[0027] Preferably, the dissolved gas concentration measuring unit measures the concentration of each component contained in the raw material gas, and the raw material gas control means controls the supply amount for each component.

[0028] The technology of the present invention involves a control method for a culture device, wherein the culture device cultures microorganisms or cells that utilize a raw gas containing a combustible gas for proliferation or production of organic matter, and the culture device comprises: a culture tank that contains a culture solution for culturing the microorganisms or cells; and a raw gas supply unit that supplies the raw gas to the culture tank. In the control method for 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 the composition ratio of the mixed gas in the space is maintained at a target value outside a preset explosion range by supplying an adjusting gas into the space based on the measured composition ratio of the mixed gas.

[0029] Effects of the Invention

[0030] According to the technology of the present invention, when culturing microorganisms or cells that utilize a raw material gas containing a combustible gas for growth or production of organic substances, it is possible to improve the culturing efficiency and safety compared to the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram for explaining the function of the culture device.

[0032] Figure 2 This is a structural diagram of the culture device according to the first embodiment.

[0033] Figure 3 This is a diagram for explaining the information in the memory.

[0034] Figure 4 This is a flow chart of the mixed gas composition ratio control process.

[0035] Figure 5 This is a structural diagram of a culture device according to a second embodiment.

[0036] Figure 6 It is a diagram showing a specific structure of a dissolved gas concentration measuring unit.

[0037] Figure 7 This is a flow chart of the dissolved gas concentration adjustment process.

[0038] Figure 8 It is a diagram showing the overall structure of a culture device according to a third embodiment.

[0039] Fig. 9 This is a diagram showing a structure for supplying raw material gas for each component.

[0040] Fig.10 This is a diagram showing a structure for recovering and reusing a culture solution.

[0041] Fig.11 This is a diagram showing the structure of separating a specific component from a culture solution.

[0042] Fig.12 It is a diagram showing the arrangement of outlets for taking out culture solutions.

[0043] Fig.13 It is a graph showing an index of the bubble diameter.

[0044] Fig.14 It is a diagram showing a surface tension reducing agent.

[0045] Fig.15 It is a diagram showing a structure for recycling exhaust gas. DETAILED DESCRIPTION

[0046] [First embodiment]

[0047] like Figure 1 As shown, as an example, the culture device 10 involved in the technology of the present invention cultures hydrogen oxidizing bacteria as microorganisms. The raw materials for the proliferation of hydrogen oxidizing bacteria include inorganic components such as ammonium sulfate in addition to hydrogen (H2), oxygen (O2) and carbon dioxide (CO2). Hydrogen is an example of a combustible gas. The culture device 10 proliferates hydrogen oxidizing bacteria in the culture solution by supplying the raw material gas to the culture solution. In addition, in the culture solution, the hydrogen oxidizing bacteria efficiently produces organic substances such as alcohols and amino acids by changing the genes of the hydrogen oxidizing bacteria. The organic substances are extracted by purifying the culture solution. The extracted organic substances are used, for example, in the manufacture of chemical products or biological products. In addition, research is being conducted on separating hydrogen oxidizing bacteria from the culture solution and using the separated hydrogen oxidizing bacteria, for example, as feed, food and fuel.

[0048] like Figure 2 As shown, the culture device 10 includes a culture tank 11, a raw gas tank 12, a culture solution tank 13, an adjustment gas tank 14, a composition ratio measuring unit 16 and a processor 17. The culture tank 11 contains a culture solution 18. As the hydrogen oxidizing bacteria 21 cultured by the culture device 10, for example, hydrogenophilic bacteria and the like described in Japanese Patent No. 6528295 can be cited. In this case, as the culture solution 18, as described in Japanese Patent No. 6528295, as an example, it is an aqueous solution obtained 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" involved in the technology of the present invention.

[0049] The culture tank 11 is connected to supply lines 12A, 13A, and 14A of the raw gas tank 12, the culture solution tank 13, and the adjustment gas tank 14. Each supply line 12A, 13A, and 14A is composed of pipes and valves, etc. A pump 22 is arranged on each supply line 12A, 13A, and 14A.

[0050] The culture fluid tank 13 contains a culture fluid 18. By driving the pump 22 on the supply path 13A, the culture fluid 18 is supplied from the culture fluid tank 13 through the supply path 13A to the culture tank 11. The supply timing and supply amount of the culture fluid 18 are controlled by the processor 17 that controls the driving of the pump 22.

[0051] The raw gas tank 12 contains a raw gas 26. As described above, as an example, the raw gas 26 is a gas containing components such as hydrogen (H2), oxygen (O2) and carbon dioxide (CO2). By driving the pump 22 on the supply path 12A, the raw gas 26 is supplied from the raw gas tank 12 to the culture tank 11 through the supply path 12A. The supply timing and supply amount of the raw gas 26 are controlled by the processor 17 that controls the drive of the pump 22. In addition, in this example, the raw gas 26 is supplied in a state of mixing a plurality of components, but the plurality of components may also be supplied individually. In this case, a supply path and a pump are provided for each component (for example, refer to Figure 6 ).

[0052] The downstream end of the supply path 12A is disposed in the culture tank 11, and a sparger 28 is provided at the downstream end. The sparger 28 is used to disperse and supply the raw material gas 26 into the culture solution 18. As the sparger 28, a ventilation tube formed of a porous material is used as an example.

[0053] A portion of the raw gas 26 supplied to the culture solution 18 is dissolved in the culture solution 18. The dissolved raw gas 26 is taken in by the hydrogen oxidizing bacteria 21 and consumed in the proliferation of the hydrogen oxidizing bacteria 21 or the production of the organic substance 29. The organic substance 29 is, for example, an alcohol or an amino acid. The raw gas 26 not dissolved in the culture solution 18 is released into the space 11A above the liquid surface 18A of the culture solution 18. The space 11A is filled with a mixed gas 31 which is the raw gas 26 not dissolved in the culture solution 18 and released. The raw gas tank 12 and the pump 22 on the supply path 12A are an example of a "raw gas supply unit".

[0054] The adjustment gas tank 14 contains an adjustment gas 33. By driving the pump 22 on the supply path 14A, the adjustment gas 33 is supplied from the adjustment gas tank 14 through the supply path 14A to the space 11A of the culture tank 11. The supply timing and supply amount of the adjustment gas 33 are controlled by the processor 17 that controls the driving of the pump 22.

[0055] The mixed gas 31 in the space 11A contains hydrogen and oxygen as components of the raw gas 26. Hydrogen is a combustible gas, and the adjustment gas 33 is used to maintain the composition ratio of the mixed gas 31 in the space 11A at a preset target value outside the explosion range. In the mixed gas 31, hydrogen and oxygen, which are combustible gases, are mixed together. In this case, an explosion phenomenon occurs according to the composition ratio of the mixed gas 31. The composition ratio of the mixed gas when the explosion phenomenon occurs is called the explosion range. As described later, a target value outside the explosion range is set in the processor 17. The target value outside the explosion range varies depending on the components of the mixed gas 31. As in this example, when the mixed gas 31 is a mixed gas containing hydrogen and oxygen, the target value outside the explosion range is generally an oxygen concentration of less than 5% or a hydrogen concentration of less than 4% in the mixed gas 31.

[0056] Furthermore, the applicant has verified through experiments that if the water vapor concentration is 7% or more, the composition ratio of the mixed gas can be maintained outside the explosion range even if the oxygen concentration is 5% or more. Therefore, in this example, as an example, regarding the target value outside the explosion range, if the water vapor concentration is 7% or more and 90% or less, the oxygen concentration is set within the range of 5% or more and 9% or less.

[0057] The experiment was conducted by the following method. As an explosion container, a stainless steel chamber with an inner diameter of 200 mm, a depth of 200 mm, and a volume of 6 L was used. The explosion container was filled with hydrogen, oxygen, carbon dioxide, and water vapor (water vapor was filled by injecting water into the explosion container and evacuating it to the saturated water vapor pressure at the temperature inside the container to gasify the water. Hydrogen, oxygen, and carbon dioxide were filled from gas cylinders through a gas introduction pipe installed in the explosion container.) After the stirring fan in the explosion container was rotated to make the gas uniform, an attempt was made to ignite the gas using a thin wire explosion device installed in the explosion container. Ignition or non-ignition was determined based on whether there was a pressure increase and whether there was a negative pressure inside the explosion container due to the generation of water. The pressure was measured by a pressure sensor (Kyowa Electronic Instruments CO., LTD., PHS-B-10MP) arranged on the upper valve of the gas discharge pipe installed in the explosion container.

[0058] Table 1 shows the experimental results of whether the mixed gas ignites depending on the gas concentration. Example 1 and Comparative Example 1 in Table 1 are both examples with a water vapor concentration of 0%, and the concentrations other than the oxygen concentration are almost the same. In Example 1, which did not ignite, the oxygen concentration was 4%, which was less than 5%, and in Comparative Example 1, which ignited, the oxygen concentration was 9%, which was more than 5%. As generally known, through Example 1 and Comparative Example 1, the following experimental results were obtained: when the water vapor concentration was 0%, if the oxygen concentration was less than 5%, it would not ignite.

[0059] Furthermore, Example 2, Example 3 and Comparative Example 2 are all examples in which the water vapor concentration is 7% or more, and only the oxygen concentration is greatly different. The oxygen concentration of Example 2 and Example 3 is 9%, and the oxygen concentration of Comparative Example 2 is 16%, which is more than 9%. According to these experimental results, when the water vapor concentration is 7% or more, even if the oxygen concentration is 5% or more, it will not ignite as long as it is 9% or less.

[0060] [Table 1]

[0061]

[0062] In addition, although it is known that there are no experimental results for the case where the hydrogen concentration is less than 4% in Table 1, if the hydrogen concentration is less than 4% instead of setting the oxygen concentration to less than 5%, the mixed gas will not ignite even when the water vapor concentration is 0%. Therefore, as a target value outside the explosion range, the hydrogen concentration of the mixed gas 31 may be set to less than 4% instead of setting the oxygen concentration of the mixed gas 31 to less than 5%.

[0063] The adjustment gas 33 is, for example, an inert gas. More specifically, in this example, carbon dioxide (CO2) is used. By supplying the adjustment gas 33 to the space 11A, the oxygen concentration or the hydrogen concentration is reduced, and the composition ratio of the mixed gas 31 is maintained at a target value outside the explosion range. In addition, as the adjustment gas 33, in addition to the inert gas, any gas can be used. For example, as the adjustment gas 33, 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 as a combustible gas to set the oxygen concentration of the mixed gas 31 to less than 5%. In this way, as the adjustment gas 33, any gas can be used, but as described later, when the mixed gas 31 is reused, it is preferred to use the components of the raw gas 26 in the adjustment gas 33.

[0064] The composition ratio measuring unit 16 measures the composition ratio of the mixed gas 31. The composition ratio measuring unit 16 is arranged on the discharge path 36 that discharges the mixed gas 31 from the space 11A of the culture tank 11. The composition ratio measuring unit 16 is composed of, for example, a gas analyzer for measuring hydrogen concentration (as an example, manufactured by HORIBA, Ltd.: model TCA-51d), a gas analyzer for measuring oxygen concentration (as an example, manufactured by HORIBA, Ltd.: model VA-5113), a gas analyzer for measuring carbon dioxide concentration (as an example, manufactured by HORIBA, Ltd.: model VA-5113) and a flow meter for measuring the total flow rate of the mixed gas 31 (as an example, manufactured by Emerson: model CMFS007M). Thus, the composition ratio measuring unit 16 can measure each component and the total flow rate of the mixed gas 31. The composition ratio measuring unit 16 outputs each measured value to the processor 17.

[0065] The processor 17 determines the supply amount of the adjustment gas 33 based on the total flow rate of the mixed gas 31 and the measured value of the oxygen concentration, so that the oxygen concentration of the mixed gas 31 is maintained below a preset upper limit. Then, the processor 17 controls the pump 22 to supply the determined supply amount of the adjustment gas 33 from the adjustment gas tank 14 to the space 11A. As a result, the oxygen concentration is reduced, and the composition ratio of the mixed gas 31 in the space 11A is maintained at a target value outside the preset explosion range. The processor 17, the adjustment gas tank 14, and the pump 22 on the supply path 14A are an example of the "composition ratio control mechanism" involved in the technology of the present invention.

[0066] In addition, a pump 37 and a three-way valve 38 for discharging the mixed gas 31 are provided on the discharge path 36. The mixed gas 31 is a gas formed by mixing the adjustment gas 33 and the raw gas 26 that is not dissolved in the culture solution 18. Therefore, the mixed gas 31 can be reused as the raw gas 26. Therefore, a circulation path 39 is connected to the discharge path 36 for returning the mixed gas 31 to the culture tank 11 via the three-way valve 38. The mixed gas 31 is supplied to the culture tank 11 again as the raw gas 26 through the circulation path 39. In this way, the mixed gas 31 containing the adjustment gas 33 is reused. The three-way valve 38 switches between a state in which the discharge path 36 is connected to the circulation path 39 and a state in which the connection between the discharge path 36 and the circulation path 39 is closed. The three-way valve 38 is used to switch whether the mixed gas 31 is transported to the circulation path 39 or discharged to the outside.

[0067] In addition, Figure 2 Although not shown in the figure for convenience, for example, the downstream end of the circulation path 39 is inserted into the culture tank 11, and a distributor 28 is provided at the downstream end of the circulation path 39 similarly to the supply path 12A.

[0068] In addition, a stirring rod 41 for stirring the culture solution 18 is provided in the culture tank 11. The stirring rod 41 is a rod having a screw provided on a support rod, and is configured so that the screw is arranged in the culture solution 18. The stirring rod 41 is driven by a motor 42 controlled by the processor 17 to rotate with the support rod as a rotation axis. Thus, the culture solution 18 is stirred. The stirring rod 41 stirs the culture solution 18 to diffuse the hydrogen oxidizing bacteria and the raw material gas 26 in the culture solution 18 to avoid local deviation.

[0069] Furthermore, the stirring rod 41 stirs the culture solution 18 to form bubbles from the culture solution 18, thereby forming a foam layer 18B on the liquid surface 18A of the culture solution 18. When a liquid film such as the foam layer 18B is formed on the liquid surface 18A of the culture solution 18, the heat capacity of the space 11A increases, which helps to suppress the explosion. The stirring rod 41 is an example of the "foam layer forming part" involved in the technology of the present invention.

[0070] In addition, a thermometer 46 for measuring the temperature T in the culture solution 18, a temperature regulator 47 for heating or cooling the culture solution 18, and a pressure gauge 48 for measuring the pressure PS in the space 11A are provided in the culture tank 11. The pressure gauge 48 is an example of a "pressure measuring unit" involved in the technology of the present invention. The culture solution 18 is maintained at a target temperature suitable for culturing hydrogen oxidizing bacteria. As an example, the target temperature is above 40°C and below 95°C. A target temperature is set for each microorganism. In the case where the hydrogen oxidizing bacteria is a hydrogenophilic bacterium, it is more preferably around 50°C. In addition to being heated to reach the target temperature, the culture solution 18 sometimes needs to be cooled. This is because the microorganisms to be cultured generate heat during proliferation, which sometimes causes the culture solution 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 solution 18 at the target temperature.

[0071] Furthermore, the culture solution 18 and the space 11A are both present in the culture tank 11, so by maintaining the temperature T of the culture solution 18 at the target temperature, the temperature in the space 11A can also be maintained at almost the same temperature. As described above, the composition ratio of the mixed gas 31 in the space 11A is maintained at a target value outside the preset explosion range. The target value also includes the water vapor concentration of the mixed gas 31. By controlling the temperature of the culture solution 18 to above 40°C, the temperature of the mixed gas 31 can be set to above 40°C. Thus, the water vapor concentration of the mixed gas 31 can also be adjusted to above 7%. The processor 17, the thermometer 46 and the temperature regulator 47 are an example of a "temperature control mechanism" involved in the technology of the present invention.

[0072] Furthermore, the processor 17 controls the pressure of the mixed gas 31 in the space 11A according to 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 gas 26 in the culture solution 18 is improved. In this way, the processor 17 ensures appropriate solubility in the culture solution 18 by controlling the pressure of the mixed gas 31. As a result, the culture efficiency of the hydrogen oxidizing bacteria 21 is improved. The pressure PS of the mixed gas 31 is adjusted to at least one of the supply amount of the raw gas 26, the discharge amount of the mixed gas 31, and the supply amount of the adjustment gas 33. The processor 17 adjusts the supply amount or discharge amount of these gases by controlling the driving of each pump 22 and the pump 37. The processor 17, the raw gas tank 12, the adjustment gas tank 14, the pumps 22 on the supply paths 12A and 14A, and the pump 37 on the discharge path 36 are an example of the "pressure control mechanism" involved in the technology of the present invention.

[0073] The processor 17 is composed of, for example, a CPU (Central Processing Unit) and a RAM (Random Access Memory), and controls each unit of the culture apparatus 10 as described above. The memory 17A is a nonvolatile memory such as a flash memory that stores various setting information.

[0074] like Figure 3 As shown, the memory 17A stores information such as the target temperature of the culture solution 18, the target pressure in the space 11A, and the target value outside the explosion range of the composition ratio of the mixed gas 31 in the space 11A as culture condition information. The processor 17 performs various controls by referring to such culture condition information.

[0075] refer to Figure 4 The flowchart shown in the figure explains the operation based on the above-mentioned structure. Figure 4 : represents the order of the composition ratio control process. The processor 17 heats the temperature of the culture solution 18 to the target temperature by driving the temperature regulator 47, for example, in a state where the culture solution 18 containing the hydrogen oxidizing bacteria 21 is contained in the culture tank 11. After the culture solution 18 reaches the target temperature, the processor 17 starts to supply the raw gas 26, thereby starting the culture process. Even after the culture process is started, the processor 17 controls the temperature of the culture solution 18 at the target temperature through the temperature regulator 47. During the culture process, the hydrogen oxidizing bacteria 21 proliferates by taking in the raw gas 26 dissolved in the culture solution 18, and produces organic substances 29. The hydrogen oxidizing bacteria 21 efficiently produces the organic substances 29 by changing genes. The time when the hydrogen oxidizing bacteria 21 produces the organic substances 29 is during or after the proliferation. A part of the raw gas 26 that is not dissolved in the culture solution 18 is released into the space 11A above the liquid surface 18A of the culture solution 18 to become a mixed gas 31.

[0076] In step S101 of the composition ratio control process, the processor 17 obtains the measured values ​​of 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 measured values ​​and obtains it as the composition ratio of the mixed gas 31.

[0077] 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. In addition, in this example, the target temperature of the culture solution 18 is set to be above 40°C. Therefore, if the saturated water vapor amount at 40°C is converted into a water vapor concentration, it is about 7%, so as long as the target temperature of the culture solution 18 is set to be above 40°C, the water vapor concentration of the mixed gas 31 can be adjusted to be above 7%. The processor 17 compares the oxygen concentration derived from the measured 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 transfers to step S104.

[0078] On the other hand, when the oxygen concentration exceeds the upper limit of the target value, that is, 9%, the processor 17 determines that the composition ratio of the mixed gas 31 is within the explosion range ("No" in step S102), and transfers to step S103. In step S103, the processor 17 supplies the adjustment gas 33 to the space 11A by driving the pump 22 of the supply path 14A. As a result, the oxygen concentration of the mixed gas 31 is reduced, and the composition ratio of the mixed gas 31 can be restored to outside the explosion range.

[0079] The processor 17 repeatedly performs such composition ratio control processing until the cultivation processing is completed ("YES" in step S104). Thus, the composition ratio of the mixed gas 31 in the space 11A can be maintained at a target value outside the explosion range.

[0080] As described above, the culture device 10 according to the technology of the present invention comprises: a composition ratio measuring unit 16 for measuring the composition ratio of the mixed gas 31 in the space 11A above the liquid surface 18A of the culture solution 18 in the culture tank 11; and a composition ratio control mechanism for maintaining the composition ratio of the mixed gas 31 in the space 11A outside the preset explosion range by supplying the adjustment gas 33 into the space 11A according to the measured composition ratio of the mixed gas 31. Therefore, in the case of culturing microorganisms (for example, hydrogen oxidizing bacteria 21) that use the raw material gas 26 containing a combustible gas (for example, hydrogen) for growth or production of organic matter, the culture efficiency and safety can be improved compared with the past.

[0081] That is, the culture apparatus 10 of the present invention maintains the composition ratio of the mixed gas 31 in the space 11A at a preset target value outside the explosion range, and therefore has improved safety compared to the case of controlling the dissolved oxygen concentration in the culture solution 18 as in Japanese Patent No. 2564008.

[0082] Furthermore, in the culture device 10 of the present invention, the culture solution 18 does not circulate in the hydrogen tank and the oxygen tank provided separately from the culture tank 11 as in Japanese Patent Application Laid-Open No. 51-038480, so the composition ratio of the raw material gas 26 in the culture solution 18 can be always maintained at an appropriate value. Therefore, the culture efficiency is improved compared with Japanese Patent Application Laid-Open No. 51-038480. Furthermore, the culture device 10 of the present invention does not control the supply amount of the raw material gas 26 such as the oxygen supply amount for the purpose of maintaining the composition ratio of the mixed gas 31 outside the explosion range as in Japanese Patent Application Laid-Open No. 2564008, so there is no shortage of the raw material gas 26 required for the proliferation of microorganisms or the production of organic substances. Therefore, the culture device 10 of the present invention improves the culture efficiency of microorganisms compared with Japanese Patent Application Laid-Open No. 2564008.

[0083] Furthermore, in this example, the adjustment gas 33 is an inert gas, so the explosion-proof effect is high and safe.

[0084] Furthermore, in this example, regarding the target value outside the explosion range of the mixed gas 31, the oxygen concentration is 5% or more and 9% or less, and the water vapor concentration is 7% or more. By setting the water vapor concentration to 7% or more, the oxygen concentration can be set higher than when it is less than 7%. Oxygen is one of the components of the raw gas 26, so by setting the oxygen concentration to a higher level, more oxygen that becomes the raw gas 26 can be supplied. Therefore, good culture efficiency can be ensured. Furthermore, even in a state where the oxygen concentration is relatively high, the composition ratio of the mixed gas 31 can be maintained at the target value outside the explosion range, so an increase in the supply amount of the adjustment gas 33 for reducing the oxygen concentration can be suppressed. As a result, unnecessary consumption of the adjustment gas 33 can be suppressed.

[0085] Furthermore, the target temperature of the culture solution 18 is set to be 40° C. or higher. If the temperature of the culture solution 18 is 40° C. or higher, the water vapor concentration of the mixed gas 31 can be adjusted to be 7% or higher. Therefore, the culture efficiency and safety can be improved.

[0086] In addition, as described above, as the target value outside the explosion range of the composition ratio of the mixed gas 31, the oxygen concentration can also be set to less than 5%. In this way, regardless of the water vapor concentration, an explosion-proof effect can be expected, so high safety can be ensured. In addition, the hydrogen concentration can also be set to less than 4% instead of setting the oxygen concentration to less than 5%. Even so, regardless of the water vapor concentration, an explosion-proof effect can be expected, and high safety can be ensured. In addition, in the case of cultivating microorganisms such as hydrogen oxidizing bacteria 21 that consume relatively more hydrogen, it is preferred to set the target value of the oxygen concentration as the target value outside the explosion range and control the oxygen concentration. This is also because, in the case of a large amount of hydrogen consumption by the microorganism, in order to increase the supply of hydrogen, it is necessary to increase the hydrogen concentration of the raw gas 26, and as a result, the hydrogen concentration of the mixed gas 31 also tends to become higher. In this way, it is difficult to control the hydrogen concentration of the mixed gas 31 to a low concentration, and the oxygen concentration is easier to control to a low concentration than the hydrogen concentration.

[0087] Furthermore, in this example, the foam layer 18B is formed on the liquid surface 18A of the culture solution 18 by using the stirring rod 41 shown as an example of the foam layer forming unit. Therefore, the heat capacity in the space 11A increases, and the explosion-proof effect is also improved.

[0088] Furthermore, in this example, there is a circulation path 39 for reusing the mixed gas 31 in the space 11A as the raw material gas 26. The mixed gas 31 contains the raw material gas 26. Therefore, compared with the case where the raw material gas 26 is not reused, unnecessary consumption of the raw material gas 26 can be suppressed. Furthermore, in this example, the adjustment gas 33 is one of the components of the raw material gas 26, so the adjustment gas 33 is also reused as a raw material. Therefore, the adjustment gas 33 can be effectively utilized. In addition, when a component other than the component of the raw material gas 26 is used as the adjustment gas 33, only the component after removing the adjustment gas 33 from the mixed gas 31 can be reused as the raw material gas 26.

[0089] Furthermore, when a component other than the component of the raw material gas 26 is used as the adjusting gas 33 , the adjusting gas 33 once exhausted from the space 11A can be reused as the adjusting gas 33 again.

[0090] Furthermore, in this example, the adjustment gas 33 is carbon dioxide. Carbon dioxide is one of the components of the raw material gas 26 in this example. Therefore, by supplying the adjustment gas 33, if a part of it is dissolved in the culture solution 18, it will also become a supplement to the raw material gas 26, and an effect can be expected from the viewpoint of culture efficiency. Moreover, when the mixed gas 31 is reused as in this example, by using carbon dioxide, which is one of the components of the raw material gas 26, as the adjustment gas 33, there is also the following advantage. That is, as described above, the adjustment gas 33 is one of the components contained in the raw material gas 26, so there is no situation where the raw material gas 26 is diluted by other components that are not used as raw materials.

[0091] Furthermore, in this example, the microorganism is hydrogen oxidizing bacteria 21. Since the hydrogen oxidizing bacteria 21 utilizes carbon dioxide as the raw material gas 26, it is also advantageous from the viewpoint of suppressing greenhouse gases.

[0092] In this example, there are provided: a pressure measuring unit (for example, a pressure gauge 48) for measuring the pressure PS in the space 11A; and a pressure control mechanism for controlling the pressure by adjusting at least one of the supply amount of the raw material gas 26, the discharge amount of the mixed gas 31, and the supply amount of the adjustment gas 33 according to the measured pressure PS. By controlling the pressure in the space 11A to the target pressure, it is possible to ensure the appropriate solubility of the raw material gas 26 in the culture solution 18.

[0093] [Second embodiment]

[0094] Figure 5 1 shows a culture device 101 according to a second embodiment. Regarding the second embodiment, descriptions of the same parts as those of the first embodiment are omitted, and descriptions will be centered on the differences. Figure 5 The structure shown is also partially omitted. In the second embodiment, the main differences from the first embodiment are the following two points. The first point is that the culture device 101 has a spraying mechanism 151 for spraying a liquid containing water in the space 11A. The second point is that the culture device 101 has: a dissolved gas concentration measuring unit 49 for measuring the dissolved gas concentration Dr of the raw material gas 26 dissolved in the culture solution 18; and a raw material gas control mechanism for controlling the supply amount of the raw material gas 26 according to the dissolved gas concentration Dr.

[0095] The spraying mechanism 151 is, for example, a sprinkler-type or atomizer-type liquid spraying mechanism, and is disposed at the top portion of the space 11A. The liquid to be sprayed may be water, but in this example, it is the culture solution 18. By spraying a liquid containing water in the space 11A, the explosion-proof effect is improved, thereby improving safety. In addition, by spraying the culture solution 18, it is possible to suppress the concentration of the raw material gas 26 in the culture solution 18 from decreasing. Thus, the decrease in the culture efficiency can be suppressed. In addition, the liquid to be sprayed may not be the culture solution 18 itself, as long as it is an aqueous solution containing at least a part of the components of the culture solution 18.

[0096] The culture solution 18 is supplied from the culture solution tank 13 to the spraying mechanism 151 via the supply path 152. The processor 17 controls the spraying amount of the culture solution 18 sprayed by the spraying mechanism 151 by the pump 22 of the supply path 152.

[0097] like Figure 6 As shown, 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 solution 18. As an example, the dissolved gas concentration measuring unit 49 is composed of a dissolved hydrogen meter (as an example, manufactured by KYOEI Electronic Research Institute: Model KM2100DH) for measuring the amount of dissolved hydrogen, a dissolved oxygen meter (as an example, manufactured by METTLE TOLEDO: Model InPro6850i) for measuring the concentration of dissolved oxygen, and a dissolved carbon dioxide meter (as an example, manufactured by METTLE TOLEDO: Model InPro5000i) for measuring dissolved carbon dioxide. The dissolved gas concentration measuring unit 49 outputs the measured value to the processor 17.

[0098] The raw gas tank 12 contains each component (hydrogen, oxygen, carbon dioxide) of the raw gas 26. In addition, a supply path 12A and a pump 22 are provided for each component. The raw gas tank 12, the supply path 12A and the pump 22 are an example of the "raw gas control mechanism" involved in the technology of the present invention.

[0099] like Figure 7As shown, in step S201 of the dissolved gas concentration adjustment process, the processor 17 obtains the measured value of the dissolved gas concentration of each component from the dissolved gas concentration measuring unit 49. In step S202, the processor 17 compares the dissolved gas concentration with the target value for each component to determine whether there is a lack of component in the raw gas 26. When there is a lack of component ("yes" in step S202), in step S203, the pump 22 on the supply path 12A is driven to supply the lack of component in the raw gas 26 to the culture tank 11. This process is repeated until the culture process is completed (step S204). Through this dissolved gas concentration adjustment process, the dissolved gas concentration of the raw gas 26 in the culture solution 18 can be maintained at an appropriate value. Compared with the case where this process is not performed, the culture efficiency of microorganisms can be improved.

[0100] In this example, the dissolved gas concentration of each component of the raw material gas 26 is measured and replenished for each insufficient component. However, the total dissolved gas concentration of the raw material gas 26 may be measured instead of each component, and the raw material gas 26 may be replenished in total. Even in this case, the shortage of the raw material gas 26 can be suppressed. Of course, if Figure 6 and Figure 7 As shown, replenishing the raw material gas 26 for each component can maintain the composition ratio of the raw material gas 26 within an appropriate range, which is preferred.

[0101] [Third Embodiment]

[0102] Figure 8 to Figure 15 The culture device 10 involved in the third embodiment shown is the same culture device as the above-mentioned embodiments, and is a culture device to which various additional structures are added. In the following description, the same symbols are basically shown for the same parts as the above-mentioned embodiments. In the third embodiment, there will also be descriptions repeated with the above-mentioned embodiments, but in terms of the correlation between the additional structures added in the third embodiment and the basic structure, the repeated parts are also convenient, so they will be described without getting tired of it. In addition, of course, at least a part of the third embodiment can be appropriately combined with the above-mentioned embodiments within the scope of no contradiction.

[0103] like Fig. 9 As shown, the culture device 10 according to the third embodiment, similarly to the above-mentioned embodiments, cultures hydrogen oxidizing bacteria as an example of a culture target microorganism. The raw material gas 25 and the like are the same.

[0104] like Fig. 9As shown, the culture device 10 includes a culture tank 11, a raw gas tank 12, a culture solution tank 13, an adjustment gas tank 14, a culture object tank 15 and a processor 17. The culture tank 11 contains a culture solution 18. The hydrogen oxidizing bacteria 21 and the culture solution 18 are the same as those in the above embodiment. In addition, a gas generating device for generating a raw gas 26 may be provided instead of or in addition to the raw gas tank 12.

[0105] The culture tank 11 is connected to supply lines 12A, 13A, 14A, and 15A for the raw gas tank 12, the culture solution tank 13, the adjustment gas tank 14, and the culture object tank 15. Each supply line 12A, 13A, 14A, and 15A is composed of pipes and valves. In addition, a pump 22 and a flow meter 23 for measuring the flow rate of the fluid flowing through each supply line are arranged on each supply line 12A, 13A, 14A, and 15A.

[0106] The culture fluid tank 13 contains a culture fluid 18. By driving the pump 22 on the supply path 13A, the culture fluid 18 is supplied from the culture fluid tank 13 through the supply path 13A to the culture tank 11. The supply timing and supply amount of the culture fluid 18 are controlled by the processor 17 that controls the driving of the pump 22.

[0107] (Pretreatment of culture medium in culture medium tank)

[0108] Furthermore, as an example, a degassing device 13B is provided in the culture solution tank 13. When the culture solution 18 is replenished from the culture solution tank 13 to the culture tank 11, the degassing device 13B removes unnecessary gas dissolved in the culture solution 18. The unnecessary gas is, for example, air and nitrogen, which have an adverse effect on the culture, such as a decrease in the culture efficiency.

[0109] In addition, the culture solution tank 13 and the raw gas tank 12 may be connected by piping, etc., so that the raw gas can be supplemented to the culture solution 18 before it is supplied to the culture tank 11. By pre-supplementing the raw gas to the culture solution 18 before it is supplied to the culture tank 11, the dissolved gas concentration of the raw gas in the culture solution 18 supplied to the culture tank 11 can be increased. As a result, the culture efficiency is sometimes improved. In this case, a dissolved gas concentration measuring unit (the same as the dissolved gas concentration measuring unit 49 described later) for measuring the dissolved gas concentration of the raw gas in the culture solution 18 can be provided in the culture solution tank 13, and the supplement amount of the raw gas can be controlled according to the measured dissolved gas concentration.

[0110] The culture object tank 15 contains hydrogen oxidizing bacteria 21 as an example of the culture object. By driving the pump 22 on the supply path 15A, the hydrogen oxidizing bacteria 21 is supplied from the culture object tank 15 through the supply path 15A to the culture tank 11. The supply timing and supply amount of the hydrogen oxidizing bacteria 21 are controlled by the processor 17 that controls the driving of the pump 22.

[0111] The raw gas tank 12 contains a raw gas 26. As described above, the raw gas 26 is a gas containing various components such as hydrogen (H2), oxygen (O2) and carbon dioxide (CO2). By driving the pump 22 on the supply path 12A, the raw gas 26 is supplied from the raw gas tank 12 to the culture tank 11 through the supply path 12A. The supply timing and supply amount of the raw gas 26 are controlled by the processor 17 that controls the drive of the pump 22.

[0112] The downstream end of the supply path 12A is arranged in the culture tank 11, and a distributor (sparger) 28 is provided at the downstream end. The distributor 28 is used to disperse and supply the raw material gas 26 into the culture solution 18. As the distributor 28, as an example, a ventilation tube formed of a porous material is used. The distributor 28 is an example of a bubble generating device that generates the raw material gas 26 as bubbles in the culture solution 18. Among the bubble generating devices, in addition to the micropore type such as the distributor 28, there are various types such as a rotating flow liquid type that generates bubbles by a high-speed rotating flow, an ejector type (also called a Venturi type) that generates bubbles by a rapid pressure change in the gas-liquid flow path, and a static mixer type that generates bubbles by the shear force of obstacles in the gas-liquid flow path. As a bubble generating device, a method other than the distributor 28 can also be used.

[0113] A portion of the raw gas 26 supplied to the culture solution 18 is dissolved in the culture solution 18. The dissolved raw gas 26 is taken in by the hydrogen oxidizing bacteria 21 and consumed in the proliferation of the hydrogen oxidizing bacteria 21 or the production of the organic substance 29. The organic substance 29 is, for example, an alcohol or an amino acid. The raw gas 26 not dissolved in the culture solution 18 is released into the space 11A above the liquid surface 18A of the culture solution 18. The space 11A is filled with a mixed gas 31 which is the raw gas 26 not dissolved in the culture solution 18 and released. The raw gas tank 12 and the pump 22 on the supply path 12A are an example of a "raw gas supply unit".

[0114] The adjustment gas tank 14 contains an adjustment gas 33. By driving the pump 22 on the supply path 14A, the adjustment gas 33 is supplied from the adjustment gas tank 14 to the space 11A of the culture tank 11 through the supply path 14A. The supply timing and supply amount of the adjustment gas 33 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 as components of the raw gas 26. Hydrogen is a combustible gas. As described later, the adjustment gas 33 is used to maintain the composition ratio of the mixed gas 31 in the space 11A at a target value outside a preset explosion range.

[0115] Furthermore, the mixed gas 31 contains components of the raw gas 26. Therefore, a portion of the mixed gas 31 can be returned to the culture tank 11 via the gas circulation path 39 and reused as the raw gas 26. The mixed gas 31 reused as the raw gas 26 is also supplied to the culture tank 11 via the distributor 28. The mixed gas 31 that is not reused is discharged. In addition, although the illustration is omitted, when discharging the mixed gas 31 that is not reused, the mixed gas 31 is diluted with an inert gas such as carbon dioxide and then released to the atmosphere.

[0116] A discharge passage 36 for taking out the mixed gas 31 is connected to the culture tank 11, and a pump 22 and a three-way valve 38 are provided on the discharge passage 36. The pump 22 generates pressure for discharging and circulating the mixed gas 31. The three-way valve 38 switches between a state in which the discharge passage 36 is connected to the gas circulation path 39 and a state in which the connection between the discharge passage 36 and the gas circulation path 39 is closed. The three-way valve 38 is used to switch whether the mixed gas 31 is transported to the gas circulation path 39 or discharged to the outside. In addition, a composition ratio measuring unit 16 for measuring the composition ratio of the mixed gas 31 is provided on the discharge passage 36. The composition ratio measuring unit 16 is used for the composition ratio control of the mixed gas 31 described later.

[0117] (Position of the outlet for the mixed gas)

[0118] Furthermore, the mixed gas outlet 34 for taking out the mixed gas 31 from the culture tank 11 is arranged at a position where the foam layer 18B formed on the liquid surface 18A of the culture solution 18 in the culture tank 11 can be taken in. The foam layer 18B acts as a membrane of the liquid covering the liquid surface 18A, and has a side effect of increasing the heat capacity of the space 11A and helping to suppress the explosion. However, on the other hand, in addition to the adverse effects on various sensors and the like arranged in the culture tank 11, there is also a concern that the hydrogen oxidizing bacteria 21 and the like may be damaged. Therefore, by arranging the mixed gas outlet 34 at a position where the foam layer 18B can be taken in, a part of the foam layer 18B can be recovered when the mixed gas 31 is taken out, thereby reducing the adverse effects caused by the foam layer 18B.

[0119] (Supply of each component of raw material gas)

[0120] And, in Figure 8 In order to reduce the complexity of the drawing, for convenience, the supply path 12A of the raw gas 26 and the gas circulation path 39 of the mixed gas 31 are shown by a single line. However, in reality, Fig. 9As shown, the supply path 12A and the gas circulation path 39 are separated according to each component such as hydrogen, oxygen and carbon dioxide, and multiple components can be supplied individually. A pump 22 and a flow meter 23 are provided on each supply path 12A and the gas circulation path 39 of each component. In addition, the distributor 28 is also provided for each component such as hydrogen (H2), oxygen (O2) and carbon dioxide (CO2). Each supply path 12A and the gas circulation path 39 of each component are connected to each distributor 28 corresponding to each component.

[0121] (Impurities removed from raw gas)

[0122] The connecting member 40 connects the supply path 12A and the gas circulation path 39 on the upstream side of the distributor 28 of each component. Thus, the supply path 12A and the gas circulation path 39 are merged into one and connected to the distributor 28. An impurity removal mechanism 51 is provided between each connecting member 40 and each distributor 28. The impurity removal mechanism 51 removes impurities from the raw gas 26 supplied to the culture tank 11.

[0123] Impurities include sulfur oxides and nitrogen oxides (NO and NO 2 , etc.) The impurity removal mechanism 51 is a mechanism that uses any one of membrane separation, cryogenic separation, physical adsorption, and chemical absorption as a method of separating impurities from the raw gas 26 .

[0124] exist Figure 8 If the culture treatment is continued, impurities will accumulate in the culture tank 11. As described later, a portion of the culture solution 18 in the culture tank 11 is temporarily taken out and returned to the culture tank 11 for reuse. When the culture solution 18 circulates, the raw gas 26 is separated from the culture solution 18, and the raw gas 26 in the culture solution 18 is also returned to the culture tank 11 via the gas recycling path 62 for reuse. In addition, a portion of the mixed gas 31 is also returned to the culture tank 11 via the gas circulation path 39 for reuse. The gas recycling path 62 and the gas circulation path 39 are connected to the upstream side of the impurity removal mechanism 51. The separated gas separated from the mixed gas 31 and the culture solution 18 to be reused is supplied to the culture tank 11 after the impurities are removed by the impurity removal mechanism 51. In this way, impurities are removed while the raw gas 26 is circulated, so that the accumulation of impurities in the culture tank 11 can be suppressed.

[0125] (Separation of components contained in mixed gas)

[0126] Furthermore, since the mixed gas 31 contains various components such as hydrogen, oxygen, and carbon dioxide, a component separation mechanism 52 is provided on the gas circulation path 39 to separate the various components contained in the mixed gas 31. The various components contained in the mixed gas 31 are separated by the component separation mechanism 52, and the separated components are supplied to the various gas circulation paths 39 provided for each component. The component separation mechanism 52 is a mechanism that uses any one of a membrane separation method, a cryogenic separation method, a physical adsorption method, and a chemical absorption method as a method of separating the various 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 the present invention.

[0127] In this way, when the raw gas 26 is supplied to the culture tank 11, by supplying each component such as hydrogen (H2), oxygen (O2) and carbon dioxide (CO2) individually, there are advantages in culture efficiency and safety. The advantage of culture efficiency is that from the perspective of culture efficiency, it is easy to adjust the raw gas 26 supplied to the culture tank 11 to an appropriate composition. In addition, the safety advantages are as follows. That is, the three elements of explosion are combustible gas, oxygen and ignition source. Before supplying the raw gas 26 to the culture tank 11, hydrogen and oxygen as combustible gases among the three elements of explosion can be separated and processed, which can further reduce the risk of explosion.

[0128] Furthermore, by means of the component separation mechanism 52, in addition to hydrogen, oxygen, and carbon dioxide, components such as nitrogen and methane can be separated as components contained in the mixed gas 31. Nitrogen, methane, and the like have the effect of reducing the solubility of the raw material gas 26 in the culture solution 18, and therefore, when the mixed gas 31 is reused, by separating them, the solubility of the raw material gas 26 can be improved.

[0129] (Circulation, recovery and reuse of culture medium)

[0130] And, if Figure 8 as well as Fig.10 As shown, a culture solution circulation path 54 is connected to the culture tank 11, and a culture solution recovery mechanism 55 is provided on the culture solution circulation path 54. The culture solution circulation path 54 takes out a part of the culture solution 18 from the culture tank 11. The culture solution recovery mechanism 55 recovers the culture solution 18 containing the organic substance 29 from the culture solution 18 taken out from the culture tank 11 through the culture solution circulation path 54. The culture solution circulation path 54 returns the culture solution 18 containing the hydrogen oxidizing bacteria 21, which is the remaining culture solution 18 after recovery by the culture solution recovery mechanism 55, to the culture tank 11. In addition, when the proliferated hydrogen oxidizing bacteria 21 are purified, for example, they are recovered in a manner different from the organic substance 29.

[0131] (Separation of dissolved gases contained in culture medium)

[0132] A gas separation mechanism 61 is provided on the downstream side of the culture solution recovery mechanism 55 on the culture solution circulation path 54. The gas separation mechanism 61 separates the gas containing the components of the raw gas 26 contained in the culture solution 18 as a separation gas from the culture solution 18 before returning the culture solution 18 to the culture tank 11. Then, the culture solution 18 from which the separation gas is separated is returned to the culture tank 11. The gas separation mechanism 61 is a separation mechanism using any one of membrane separation, cryogenic separation, physical adsorption and chemical absorption. Hydrogen storage alloys can be used for hydrogen separation.

[0133] (Recycling of raw material gas from culture medium)

[0134] A portion of the separated gas separated by the gas separation mechanism 61 is returned to the culture tank 11 via the gas recycling path 62 and the gas circulation path 39 of the mixed gas 31. Then, it is reused as the raw material gas 26. Therefore, the utilization efficiency of the raw material gas 26 is improved.

[0135] (Explosion suppression when recycling raw material gas from culture medium)

[0136] Furthermore, the separated gas is returned to the culture tank 11 via the gas circulation path 39, and is therefore separated into components such as hydrogen, oxygen, and carbon dioxide by the component separation mechanism 52 as described above. However, the separated gas may be separated into components such as hydrogen, oxygen, and carbon dioxide in the gas recycling path 62, rather than being separated for each component in the component separation mechanism 52. These separated components are reused via the gas circulation path 39 provided for each component. The separation of the separated gas for each component in the gas recycling path 62 may also be performed, for example, by the gas separation mechanism 61 that separates the gas from the culture solution 18.

[0137] In this way, when the separated gas is reused, hydrogen and oxygen as combustible gases can be separated, so the safety in the gas reuse path 62 is improved. In this way, from the perspective of safety, it is preferred to separate hydrogen as combustible gas from the culture solution 18 taken out from the culture tank 11 as far as possible on the upstream side. And, as the order of separating the components, it is preferred to separate hydrogen first, and then separate oxygen and carbon dioxide. This gas separation mechanism 61 has the function of suppressing explosion, and is therefore an example of the "explosion suppression mechanism" involved in the technology of the present invention.

[0138] Furthermore, if the components of the separation gas are separated in the gas separation mechanism 61 in this way, in addition to being reused as the raw gas 26, carbon dioxide can also be returned to the adjustment gas tank 14 and reused as the adjustment gas 33. When the separation gas is separated into components, the gas separation mechanism 61 is also an example of the "second component separation mechanism" involved in the technology of the present invention. In the gas separation mechanism 61, in addition to hydrogen, oxygen and carbon dioxide, components such as nitrogen and methane that reduce the solubility of the raw gas 26 can also be separated, similarly to the component separation mechanism 52.

[0139] (Separation of specific components from culture medium)

[0140] And, if Fig.11 As shown, by utilizing the separation mechanism 65 which is the same as the gas separation mechanism 61 and the component separation mechanism 52, in addition to separating the gas from the culture solution 18, specific components contained in the culture solution 18 can also be separated. Examples of specific components include ammonia and ammonium compounds. Ammonia and ammonium compounds serve as a nutrient source for hydrogen oxidizing bacteria 21. By separating them, they can be reused while adjusting the supply amount.

[0141] By separating the various components contained in the mixed gas 31 and the culture solution 18 in this manner, 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 .

[0142] exist Fig.10 In the embodiment, the culture solution recovery mechanism 55 is connected to a recovery liquid tank 57 storing the recovered culture solution 18, i.e., the recovery liquid 58, via a recovery path 56. The recovery liquid 58 is transferred from the culture solution recovery mechanism 55 to the recovery liquid tank 57 through the recovery path 56. The recovery path 56 is provided with a pump 22 for transferring the recovery liquid 58.

[0143] A part of the recovery liquid 58 contained in the recovery liquid tank 57 is transferred to a purification device (not shown). In the purification device, the organic substance 29 produced by culturing the hydrogen oxidizing bacteria 21 is extracted from the recovery liquid 58.

[0144] (Treatment to reduce the concentration of dissolved combustible gas in the recovery liquid)

[0145] The culture device 10 is provided with a concentration reducing mechanism for reducing the concentration of dissolved hydrogen contained in the recovery liquid 58 compared with the culture liquid 18 in the culture tank 11. As an example, the concentration reducing mechanism is formed by extending the total length L of the section from the culture tank 11 to the culture liquid recovery mechanism 55 in the culture liquid circulation path 54 to the length required for concentration reduction. Specifically, the total length L of the section is the length required to reduce the concentration of dissolved hydrogen contained in the recovery liquid 58 to less than 1 / 10 of the concentration of dissolved hydrogen contained in the culture liquid 18 in the culture tank 11. The culture liquid 18 taken out from the culture tank 11 contains hydrogen-consuming hydrogen-oxidizing bacteria 21, and the hydrogen-oxidizing bacteria 21 also consumes hydrogen in the culture liquid circulation path 54. The longer the culture liquid circulation path 54 is, the more time it can ensure that hydrogen is consumed by the hydrogen-oxidizing bacteria 21. As a result, the utilization efficiency of hydrogen is improved. In addition, if hydrogen is consumed in the section from the culture liquid recovery mechanism 55 of the culture liquid circulation path 54, the dissolved hydrogen concentration of the recovery liquid 58 recovered by the culture liquid recovery mechanism 55 is reduced. As a result, the hydrogen released from the recovery liquid 58 is also reduced, so the explosion risk in the recovery liquid tank 57 is also reduced, and safety can be ensured. The culture solution circulation path 54 whose total length L of the above section is the length required for concentration reduction is an example of the "concentration reduction mechanism" involved in the technology of the present invention.

[0146] Furthermore, instead of extending the total length L of the section of the culture solution circulation path 54, the flow rate of the culture solution 18 flowing through the section may be reduced. As a result, the time from when the culture solution 18 taken out from the culture tank 11 is transferred to the culture solution recovery mechanism 55 is extended, and thus the time for consuming hydrogen in the taken out culture solution 18 can be extended. As a result, the same effect as when the total length L of the section is extended can be obtained. The flow rate of the culture solution 18 can be adjusted, for example, by controlling the suction volume per unit time of the pump 22. The suction volume of the pump 22 is controlled by the processor 17. The flow rate adjustment mechanism composed of such a processor 17 and the pump 22 is also an example of the "concentration reduction mechanism" involved in the technology of the present invention.

[0147] (Downstream side of recovery liquid tank 57)

[0148] A purification target separation mechanism 59 is provided on the downstream side of the recovery liquid tank 57. The purification target separation mechanism 59 separates a portion of the recovery liquid 58 containing the organic substance 29 as a purification target from the recovery liquid 58 and sends the separated purification target to the purification device. The remaining recovery liquid 58 other than the recovery liquid 58 separated as the purification target by the purification target separation mechanism 59 is returned to the culture tank 11 as the culture liquid 18 via the liquid recycling path 63 and the culture liquid circulation path 54 and is reused.

[0149] As in Fig.10As shown in the enlarged view of a part in FIG. 1 , the culture solution recovery mechanism 55 includes a pump 22 and a liquid separation mechanism 64. The pump 22 generates a circulation pressure for circulating the culture solution 18. Similar to the purification object separation mechanism 59, the liquid separation mechanism 64 separates a part of the culture solution 18 containing the organic matter 29 from the culture solution 18 taken out from the culture tank 11, and sends the separated culture solution 18 as the recovery solution 58 to the recovery path 56. The remaining culture solution 18 is sent to the gas separation mechanism 61.

[0150] (Position of the culture solution outlet on the culture solution circulation path)

[0151] And, if Fig.12 As shown, the culture solution circulation path 54 includes a take-out port 54A for taking out the culture solution 18 from the culture tank 11 and a return port 54B for returning a portion of the taken-out culture solution 18 to the culture tank 11 .

[0152] The dissolved gas concentration of the raw gas 26 is low on the upper side of the culture solution 18 in the culture tank 11 in the height direction, and is high on the lower side. The outlet 54A is set in a low concentration area where the dissolved gas concentration is relatively low, and the return port 54B is set in a high concentration area where the dissolved gas concentration is relatively high. More specifically, the outlet 54A is set in a low concentration area where the dissolved gas concentration of the culture solution 18 in the culture tank 11 is lower than the average value Av.

[0153] Thus, when a part of the culture solution 18 is taken out from the culture tank 11 in order to circulate the culture solution 18 , it is easy to eliminate concentration unevenness of the dissolved gas concentration of the culture solution 18 in the culture tank 11 .

[0154] (Stirring of culture tanks, temperature adjustment, and sensing of various information)

[0155] And, in Figure 8 In the culture tank 11, a stirring rod 41 for stirring the culture solution 18 is provided. The stirring rod 41 is a rod having a screw 41A provided on a support rod, and the screw 41A is arranged in the culture solution 18. The stirring rod 41 is driven by a motor 42 controlled by the processor 17 to rotate with the support rod as a rotation axis. Thus, the culture solution 18 is stirred. The stirring rod 41 stirs the culture solution 18 to diffuse the hydrogen oxidizing bacteria 21 and the raw material gas 26 in the culture solution 18 to avoid local deviation.

[0156] Furthermore, the stirring rod 41 stirs the culture solution 18 to generate bubbles from the culture solution 18 , thereby forming the foam layer 18B on the liquid surface 18A of the culture solution 18 .

[0157] In addition, the culture tank 11 is provided 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 gas 26 dissolved in the culture solution 18. The density measuring unit 50 measures the density ρ of the hydrogen oxidizing bacteria 21 in the culture solution 18 in the culture tank 11.

[0158] The culture solution 18 is maintained at a target temperature suitable for culturing the hydrogen oxidizing bacteria 21. As an example, the target temperature is above 40°C and below 95°C. A target temperature is set for each microorganism. In the case where the hydrogen oxidizing bacteria 21 is a hydrogenophilic bacterium, it is more preferably around 50°C. In addition to being heated to reach the target temperature, the culture solution 18 sometimes needs to be cooled. This is because the microorganisms to be cultured generate heat during proliferation, which sometimes causes the culture solution 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 solution 18 at the target temperature.

[0159] Furthermore, the processor 17 controls the pressure of the mixed gas 31 in the space 11A according to 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 gas 26 in the culture solution 18 is improved. In this way, the processor 17 ensures appropriate solubility in the culture solution 18 by controlling the pressure of the mixed gas 31. As a result, the culture efficiency of the hydrogen oxidizing bacteria 21 is improved. The pressure PS of the mixed gas 31 is adjusted to at least one of the supply amount of the raw gas 26, the discharge amount of the mixed gas 31, and the supply amount of the adjustment gas 33. The processor 17 adjusts the supply amount or discharge amount of these gases by controlling the driving of each pump 22.

[0160] More specifically, the dissolved gas concentration measuring unit 49 measures the concentration of each component (hydrogen, oxygen, and carbon dioxide) contained in the raw gas 26 dissolved in the culture solution 18. As an example, the dissolved gas concentration measuring unit 49 is composed of a dissolved hydrogen meter (as an example, manufactured by KYOEI Electronic Research Institute: Model KM2100DH) for measuring the dissolved hydrogen concentration (Dr(H2)), a dissolved oxygen meter (as an example, manufactured by METTLE TOLEDO: Model InPro6860i) for measuring the dissolved oxygen concentration (Dr(O2)), and a dissolved carbon dioxide meter (as an example, manufactured by METTLE TOLEDO: Model InPro5000i) for measuring the dissolved carbon dioxide concentration (Dr(CO2)).

[0161] The dissolved gas concentration measuring unit 49 outputs the measured value to the processor 17 .

[0162] like Fig. 9 As shown, the raw material gas tank 12 contains each component (hydrogen, oxygen, carbon dioxide) of the raw material gas 26. In addition, a supply path 12A and a pump 22 are provided for each component.

[0163] The processor 17 obtains 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 for each component, and supplies the insufficient component in the raw gas 26 to the culture tank 11. The processor 17 can maintain the dissolved gas concentration of the raw gas 26 in the culture solution 18 at an appropriate value by controlling the supply amount of each component of the raw gas 26.

[0164] The density measuring unit 50 measures the density ρ of the culture object in the culture solution 18 in the culture tank 11. As an example, the density measuring unit 50 is composed of a total cell density sensor (for example, manufactured by HAMILTON: model Dencytee RS485). In this example, the culture object is hydrogen oxidizing bacteria 21, so the density measuring unit 50 measures the density ρ of the hydrogen oxidizing bacteria 21 in the culture solution 18. There is a positive correlation between the density ρ of the hydrogen oxidizing bacteria 21 and the consumption of the raw material gas 26 consumed by the hydrogen oxidizing bacteria 21. By measuring the density ρ, for example, it can be used for calculating the consumption of the raw material gas 26 consumed by the hydrogen oxidizing bacteria 21, or for process checks to verify whether the consumption of the raw material gas 26 is appropriate relative to the amount of hydrogen oxidizing bacteria 21.

[0165] The water level meter 66 measures the water level of the culture solution 18 in the culture tank 11, that is, the height of the liquid surface 18A. The amount of the culture solution 18 in the culture tank 11 can be determined based on the water level of the culture solution 18 measured by the water level meter 66. The water level meter 66 is used for process inspection of whether the amount of the culture solution 18 is appropriate and calculation of the necessary replenishment amount of the culture solution 18.

[0166] In addition, an explosion vent 67 is provided in the culture tank 11. The explosion vent 67 is used to safely release the pressure in the culture tank 11 by destroying it earlier than other parts in the event of an explosion in the culture tank 11, thereby suppressing the expansion of damage. As for the vicinity of the explosion vent 67, a part that will not cause great damage even if the pressure is released or a part where measures such as preventing the expansion of damage are implemented are selected.

[0167] The processor 17 is composed of, for example, a CPU (Central Processing Unit) and a RAM (Random Access Memory), and controls each unit of the culture apparatus 10 as described above. The memory 17A is a nonvolatile memory such as a flash memory that stores various setting information.

[0168] (Control of Bubble Diameter of Raw Gas Supplied to Culture Tank)

[0169] Regarding the bubble diameter of the raw gas 26 generated in the culture solution 18 of the culture tank 11, d90 is set to be less than 1000 μm. Fig.13 As shown, d90 refers to the bubble diameter at which the cumulative volume becomes 90% of the total volume of all bubbles when the volumes of the bubbles in the entire bubble are added in order from the smallest diameter. Fig.13 The mountain-shaped distribution based on the bar graph shown is a histogram of the bubble diameters of bubbles generated in the culture solution 18, with the horizontal axis being the bubble diameter and the vertical axis being the frequency. If the volume of such bubble diameters is accumulated, it becomes as follows: Fig.13 The line graph with a rising right shoulder is shown. d90 is the bubble diameter at which the ratio of the cumulative volume becomes 90% of the total volume. In the culture device 10, as an example, the bubble diameter is set to be less than 1000μm. This bubble diameter is determined, for example, based on the specifications of the bubble generating device such as the distributor 28. Regarding the bubble diameter, by setting d90 to less than 1000μm, the solubility of the raw gas 26 in the culture solution 18 can be improved. A more preferred bubble diameter is a d90 of less than 500μm, and it is further preferred to set d90 to less than 200μm. By setting it to such a bubble diameter, the high solubility of the raw gas 26 can be ensured even under conditions where the raw gas 26 is difficult to dissolve, such as when the temperature of the culture solution 18 is high or the depth of the culture tank 11 is shallow.

[0170] (Surface tension reducing agent)

[0171] And, if Fig.14 As shown, by adding a surface tension reducer, the culture solution 18 can contain a surface tension reducer. If the surface tension of the culture solution 18 is reduced, the bubbles are easily reduced in diameter, so that the solubility of the raw gas 26 containing hydrogen as a combustible gas can be improved. The surface tension of the culture solution 18 is preferably set to 65mN / m or less. If the surface tension is set to this degree, it is easy to set the d90 of the bubble diameter to 1000μm or less. The amount of the surface tension reducer added is determined in a manner that the surface tension becomes this value. The surface tension of the culture solution 18 is more preferably 55mN / m or less, and is further preferably set to 45mN / m or less. By setting such a surface tension, it is easier to make the bubble diameter smaller.

[0172] (Recycling of waste gas)

[0173] And, if Fig.15 As shown, the culture device 10 can reuse the waste gas containing carbon dioxide exhausted from the external device as the raw gas 26 of the culture device 10. The external device is another device other than the culture device 10, for example, it can be another device in the same facility as the facility where the culture device 10 operates, or it can be another device in another facility (factory, etc.). When the waste gas is reused, the carbon dioxide is separated from the waste gas by the component separation mechanism 52, and the separated carbon dioxide is reused as the raw gas 26. In this way, by reusing the carbon dioxide contained in the waste gas, it can help reduce the amount of carbon dioxide emissions.

[0174] In the above example, as a microorganism, hydrogen oxidizing bacteria 21 is used as an example for explanation, but the technology of the present invention can also be applied to microorganisms or cells other than hydrogen oxidizing bacteria 21. As a microorganism, for example, acetogenic bacteria such as ethanol Clostridium and methane assimilating bacteria such as Methylococcus can also be used. In the case of acetogenic bacteria, the components of the raw gas 26 are hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2) as combustible gases. In the case of methane assimilating bacteria, the components of the raw gas 26 are methane (CH4) and air as combustible gases. In the case of methane assimilating bacteria, the components of the raw gas 26 are methane (CH4) and air as combustible gases. In addition, a cell refers to a morphological and / or functional unit constituting a living body, and the living body that is the source of the cell is not particularly limited, and can be an animal or a plant. The cell can be a strain of cells or a genetically recombinant cell, and can also include an artificial cell. For example, CHO cells (Chinese hamster ovary cells), HEK293 cells (Human Embryonic Kidney cells 293), Sf9 cells (Spodoptera frugiperda cells 9), and the like can be cited.

[0175] The various processors mentioned above are not limited to general-purpose processors, i.e., CPUs, that execute software (programs) and function as various processing units. They also include processors, i.e., programmable logic devices (PLDs), ASICs (Application Specific Integrated Circuits), etc., that have circuit structures specially designed to perform specific processing, i.e., dedicated circuits, etc., whose circuit structures can be changed after manufacturing, such as FPGAs (Field Programmable Gate Arrays).

[0176] Furthermore, as the hardware configuration of these various processors, more specifically, a circuit (circuitry) formed by combining circuit elements such as semiconductor elements can be used.

[0177] The above-described contents and illustrated contents are detailed descriptions of the parts involved in the technology of the present invention, and are only an example of the technology of the present invention. For example, the descriptions related to the above-described structure, function, action and effect are descriptions related to an example of the structure, function, action and effect of the parts involved in the technology of the present invention. Therefore, it is self-evident that unnecessary parts can be deleted from the above-described contents and illustrated contents, or new elements can be added, or replacements can be made without departing from the scope of the purpose of the technology of the present invention. Furthermore, in order to avoid complexity and facilitate understanding of the parts involved in the technology of the present invention, the above-described contents and illustrated contents have omitted descriptions related to technical common sense that does not need to be specifically explained in terms of the technology that can implement the present invention.

[0178] All disclosed contents of Japanese Patent Application No. 2022-140319 filed on September 2, 2022 and Japanese Patent Application No. 2023-125055 filed on July 31, 2023 are incorporated into this specification by reference. In addition, all documents, patent applications, and technical standards described in this specification are incorporated into this specification by reference to the same extent as if each document, patent application, and technical standard was specifically and individually described as being incorporated by reference.

[0179] The following additional notes are further disclosed regarding the above-mentioned embodiment.

[0180] <Note 1>

[0181] A culture device for culturing microorganisms or cells that utilize a raw material gas containing a combustible gas for growth or production of organic matter, the culture device comprising:

[0182] A culture tank containing a culture solution for culturing the microorganisms or cells;

[0183] A raw material gas supply unit, which supplies the raw material gas to the culture tank;

[0184] a composition ratio measuring unit for measuring the composition ratio of the mixed gas existing in the space above the liquid surface of the culture solution in the culture tank; and

[0185] The composition ratio control means maintains the composition ratio of the mixed gas in the space at a target value outside a preset explosion range by supplying an adjustment gas into the space according to the measured composition ratio of the mixed gas.

[0186] <Note 2>

[0187] The culture device according to Supplementary Note 1, wherein:

[0188] The adjustment gas is an inert gas.

[0189] <Note 3>

[0190] The culture device according to Supplement 1 or Supplement 2, wherein:

[0191] The target value outside the explosion range is set to an oxygen concentration of less than 5% or a hydrogen concentration of less than 4%.

[0192] The composition ratio control mechanism controls the composition ratio based on the target value.

[0193] <Note 4>

[0194] The culture device according to any one of Supplement 1 to Supplement 3, wherein:

[0195] Regarding the target values ​​outside the explosion range, the oxygen concentration is 5% or more and 9% or less, and the water vapor concentration is 7% or more,

[0196] The composition ratio control mechanism controls the composition ratio based on the target value.

[0197] <Note 5>

[0198] The culture device according to any one of Supplementary Notes 1 to 4, comprising a temperature control mechanism for controlling the temperature of the culture solution.

[0199] <Note 6>

[0200] The culture device according to Supplement 5 referring to Supplement 4, wherein:

[0201] The temperature control mechanism controls the temperature of the culture solution to be above 40°C.

[0202] <Note 7>

[0203] The culture device according to any one of Supplementary Notes 1 to 6, comprising a spraying mechanism for spraying a liquid containing water in the space.

[0204] <Note 8>

[0205] The culture device according to Supplementary Note 7, wherein:

[0206] The liquid is an aqueous solution containing at least a part of the components of the culture solution.

[0207] <Note 9>

[0208] The culture device according to any one of Supplementary Notes 1 to 8, comprising a foam layer forming portion that forms a foam layer on a liquid surface of the culture liquid.

[0209] <Note 10>

[0210] The culture apparatus according to any one of Supplementary Notes 1 to 9, comprising a circulation path for reusing the mixed gas in the space as a raw material gas.

[0211] <Note 11>

[0212] The culture device according to any one of Supplementary Notes 1 to 10, wherein

[0213] The combustible gas is hydrogen.

[0214] <Note 12>

[0215] The culture device according to Supplementary Note 11, wherein

[0216] The raw material gas includes hydrogen, oxygen and carbon dioxide.

[0217] <Note 13>

[0218] The culture device according to Supplementary Note 12, wherein:

[0219] The adjusting gas is carbon dioxide.

[0220] <Note 14>

[0221] The culture device according to Supplementary Note 13, wherein

[0222] The microorganism is a hydrogen oxidizing bacterium.

[0223] <Note 15>

[0224] The culture device according to any one of Supplementary Notes 1 to 14, comprising:

[0225] a pressure measuring unit for measuring the pressure in the space; and

[0226] The pressure control mechanism controls the pressure by adjusting at least one of a supply amount of the raw material gas, a discharge amount of the mixed gas, and a supply amount of the adjustment gas according to the measured pressure.

[0227] <Note 16>

[0228] The culture device according to any one of Supplementary Notes 1 to 15, comprising:

[0229] a dissolved gas concentration measuring unit for measuring the dissolved gas concentration of the raw material gas dissolved in the culture solution; and

[0230] The raw material gas control mechanism controls the supply amount of the raw material gas according to the dissolved gas concentration.

[0231] <Note 17>

[0232] The culture device according to Supplementary Note 16, wherein

[0233] The dissolved gas concentration measuring unit measures the concentration of each component contained in the raw gas.

[0234] The raw material gas control means controls the supply amount for each of the components.

[0235] <Note 18>

[0236] A control method for a culture device, wherein the culture device cultivates microorganisms or cells that use a raw material gas containing a combustible gas for proliferation or production of organic matter, the culture device comprising: a culture tank that contains a culture solution for cultivating the microorganisms or cells; and a raw material gas supply unit that supplies the raw material gas to the culture tank, in which:

[0237] measuring the composition ratio of the mixed gas present in the space above the liquid surface of the culture solution in the culture tank,

[0238] The composition ratio of the mixed gas in the space is maintained at a target value outside a preset explosion range by supplying an adjusting gas into the space according to the measured composition ratio of the mixed gas.

Claims

1. A culture device for culturing microorganisms or cells that utilize a raw material gas containing a combustible gas for growth or production of organic matter, the culture device comprising: A culture tank containing a culture solution for culturing the microorganism or the cell; A raw material gas supply unit, which supplies the raw material gas to the culture tank; a composition ratio measuring unit for measuring the composition ratio of the mixed gas existing in the space above the liquid surface of the culture solution in the culture tank; and The composition ratio control means maintains the composition ratio of the mixed gas in the space at a target value outside a preset explosion range by supplying an adjustment gas into the space according to the measured composition ratio of the mixed gas.

2. The culture device according to claim 1, wherein: The adjustment gas is an inert gas.

3. The culture device according to claim 1, wherein: The target value outside the explosion range is set to an oxygen concentration of less than 5% or a hydrogen concentration of less than 4%. The composition ratio control mechanism controls the composition ratio based on the target value.

4. The culture device according to claim 1, wherein: The target values ​​outside the explosion range are: oxygen concentration is 5% or more and 9% or less, and water vapor concentration is 7% or more, The composition ratio control mechanism controls the composition ratio based on the target value. The culture device according to claim 1 , comprising a temperature control mechanism for controlling the temperature of the culture solution.

6. The culture device according to claim 4 or 5, wherein: The temperature control mechanism controls the temperature of the culture solution to be above 40°C. The culture device according to claim 1 , comprising a spraying mechanism for spraying a liquid containing water in the space.

8. The culture device according to claim 7, wherein: The liquid is an aqueous solution containing at least a part of the components of the culture solution. 9 . The culture device according to claim 1 , comprising a foam layer forming portion for forming a foam layer on a liquid surface of the culture liquid. 10 . The culture apparatus according to claim 1 , comprising a circulation path for reusing the mixed gas in the space as the raw material gas.

11. The culture device according to claim 1, wherein: The combustible gas is hydrogen.

12. The culture device according to claim 11, wherein: The raw material gas includes hydrogen, oxygen and carbon dioxide.

13. The culture device according to claim 12, wherein: The adjusting gas is carbon dioxide.

14. The culture device according to claim 13, wherein: The microorganism is a hydrogen oxidizing bacterium.

15. The culture device according to claim 1, comprising: a pressure measuring unit for measuring the pressure in the space; and The pressure control mechanism controls the pressure by adjusting at least one of a supply amount of the raw material gas, a discharge amount of the mixed gas, and a supply amount of the adjustment gas according to the measured pressure.

16. The culture device according to claim 1, comprising: a dissolved gas concentration measuring unit for measuring the dissolved gas concentration of the raw material gas dissolved in the culture solution; and The raw material gas control mechanism controls the supply amount of the raw material gas according to the dissolved gas concentration.

17. The culture device according to claim 16, wherein: The dissolved gas concentration measuring unit measures the concentration of each component contained in the raw gas. The raw material gas control means controls the supply amount for each of the components.

18. A control method for a culture device, wherein the culture device cultivates microorganisms or cells that use a raw material gas containing a combustible gas for proliferation or production of organic matter, the culture device comprising: a culture tank that contains a culture solution for cultivating the microorganisms or cells; and a raw material gas supply unit that supplies the raw material gas to the culture tank, wherein the control method for the culture device, measuring the composition ratio of the mixed gas present in the space above the liquid surface of the culture solution in the culture tank, The composition ratio of the mixed gas in the space is maintained at a target value outside a preset explosion range by supplying an adjusting gas into the space according to the measured composition ratio of the mixed gas.

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