Batch culturing device

Abstract

A batch culturing device 1a comprises: a reaction tank 10; a shaft 20; and a plurality of light sources 30. The reaction tank 10 can accommodate a culture solution for photosynthetic microorganisms. The shaft 20 extends along a lateral surface 11 inside the reaction tank 10 at a central portion of the inside of the reaction tank 10. The plurality of light sources 30 are arranged inside the reaction tank 10. The plurality of light sources 30 include a first light source 31 and a second light source 32. When z-direction is the direction in which the shaft 20 extends, in a surface perpendicular to the z-direction, an angle θ1 formed between a first straight line L1 that connects the center of the first light source 31 and the center of the shaft 20 as viewed in the z-direction, and a second straight line L2 that connects the center of the second light source 32 and the center of the shaft 20 as viewed in the z-direction satisfies the condition of 90°<θ1≤180°.

Description

Batch culture equipment

[0001] The present disclosure relates to a batch culture device.

[0002] Conventionally, a cultivation device for photosynthetic microorganisms has been known.

[0003] For example, Patent Document 1 describes a biological culture system for culturing photosynthetic organisms such as microalgae. This biological culture system includes a liquid reservoir, a culture vessel, a first light intensity measuring unit, and a control unit. The liquid reservoir holds a light-absorbing liquid that absorbs light in a second wavelength range, which is shorter than the first wavelength range, more than light in the first wavelength range. The culture vessel is placed inside the liquid reservoir and stores a culture liquid containing a photosynthetic organism to be cultured. The first light intensity measuring unit measures the amount of light received by the culture vessel. The control unit controls the liquid depth from the liquid surface of the light-absorbing liquid to the culture vessel inside the liquid reservoir based on the measurement result of the first light intensity measuring unit.

[0004] Patent Document 2 describes an expandable vertical unit for culturing photosynthetic microorganisms. The vertical unit includes at least one sealable photobioreactor, a column operatively engaged with the photobioreactor, and at least one light source. The at least one light source and the column are aligned along the longitudinal axis of the photobioreactor. The column is configured to control parameters including the temperature inside the photobioreactor, the intensity of light emitted by the light source, the duration of illumination by the light source, the frequency of illumination, and the wavelength of light emitted by the light source.

[0005] Patent Document 3 describes a photobioreactor used in a circulating culture method for photosynthetic microalgae. The photobioreactor includes a first culture section, a second culture section, and a pump section. The pump section is connected to the first culture section and the second culture section so as to circulate a culture solution between the first culture section and the second culture section. A culture tank and a first light source are connected to the first culture section. The first light source emits light capable of photosynthesis during the culture of photosynthetic microalgae. The first light source is disposed inside the culture tank. The first light source may also be disposed on the outer surface of the culture tank.

[0006] International Publication No. 2014 / 132348 Patent Publication No. 2022-517443 Patent Publication No. 2012-23990

[0007] The present disclosure provides a batch culture device that is advantageous in terms of efficiency and scale-up of photosynthetic microorganism culture.

[0008] The batch culture apparatus of the present disclosure comprises: a reaction tank capable of accommodating a culture solution of photosynthetic microorganisms; an axis extending along the side surface of the reaction tank at the center of the reaction tank; and a plurality of light sources arranged inside the reaction tank, wherein the plurality of light sources include a first light source and a second light source; the direction in which the axis extends is defined as the z direction; and an angle θ1 formed in a plane perpendicular to the z direction by a first line that is a line connecting the center of the first light source and the center of the axis when viewed from the z direction, and a second line that is a line connecting the center of the second light source and the center of the axis when viewed from the z direction satisfies the condition of 90°<θ1≦180°.

[0009] According to the present disclosure, a batch culture apparatus can be provided that is advantageous from the viewpoints of efficiency and scale-up of photosynthetic microorganism culture.

[0010] FIG. 1 is a diagram schematically showing an example of a batch culture apparatus according to the present disclosure. FIG. 2 is a diagram schematically showing an example of an arrangement of multiple light sources in the batch culture apparatus according to the present disclosure. FIG. 3 is a diagram schematically showing another example of an arrangement of multiple light sources in the batch culture apparatus according to the present disclosure. FIG. 4 is a diagram schematically showing yet another example of an arrangement of multiple light sources in the batch culture apparatus according to the present disclosure. FIG. 5 is a diagram schematically showing yet another example of an arrangement of multiple light sources in the batch culture apparatus according to the present disclosure. FIG. 6 is a diagram schematically showing yet another example of an arrangement of multiple light sources in the batch culture apparatus according to the present disclosure. FIG. 7 is a diagram schematically showing an arrangement of light sources in a batch culture apparatus according to a comparative example. FIG. 8 is a diagram schematically showing a batch culture apparatus according to another comparative example. FIG. 9 is a plan view showing a fixture of the batch culture apparatus according to the present disclosure. FIG. 10 is a diagram schematically showing another example of the batch culture apparatus according to the present disclosure. Fig. 11 is a diagram schematically illustrating yet another example of the batch culture apparatus of the present disclosure. Fig. 12 is a graph showing the relationship between the specific growth rate of photosynthetic microorganisms and the number of light sources.

[0011] (Knowledge forming the basis of the present disclosure) As societal demand for decarbonization increases, material production using photosynthetic microorganisms is attracting attention as a next-generation technology with a low environmental impact. Photosynthesis is a reaction that uses light energy to produce organic matter from water and carbon dioxide in the air at room temperature and atmospheric pressure. Coupled with recent advances in genetic engineering technology, improvements in the productivity of a wide variety of compounds have been reported by modifying genes related to the metabolism or biosynthesis of photosynthetic microorganisms.

[0012] The light intensity of the light source is considered to be important for the cultivation of photosynthetic microorganisms. For example, in the biological culture system described in Patent Document 1, the amount of light received by the culture vessel is measured to control the liquid depth from the liquid surface of the light absorbing liquid to the culture vessel. In the vertical unit described in Patent Document 2, parameters related to the light emitted by the light source are controlled. The photobioreactor described in Patent Document 3 is used in a circulating culture method for photosynthetic microalgae, and is not intended for batch operation of photosynthetic microorganisms.

[0013] According to the studies of the present inventors, when culturing photosynthetic microorganisms using batch operations, it has been found that in order to scale up the cultivation to a commercial scale, it is difficult to efficiently cultivate photosynthetic microorganisms simply by optimizing the light intensity of the light source.

[0014] Therefore, the present inventors conducted extensive research to develop a batch culture apparatus that can easily increase the efficiency of photosynthetic microorganism cultivation while also enabling scale-up. As a result, the present inventors discovered that by arranging multiple light sources under predetermined conditions inside the reaction tank of the batch culture apparatus, it is possible to easily increase the efficiency of photosynthetic microorganism cultivation while also enabling scale-up. Based on this new finding, the batch culture apparatus of the present disclosure was devised.

[0015] (Embodiments) Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments. In the accompanying drawings, the z direction indicates the direction of gravity.

[0016] FIG. 1 is a schematic diagram illustrating an example of a batch culture apparatus for photosynthetic microorganisms. As shown in FIG. 1, the batch culture apparatus 1a includes a reaction vessel 10, a shaft 20, and multiple light sources 30. The reaction vessel 10 can contain a culture solution for photosynthetic microorganisms. The culture solution includes, for example, photosynthetic microorganisms and a culture medium. The shaft 20 extends along the inner side surface 11 of the reaction vessel 10 at the center of the interior of the reaction vessel 10. The multiple light sources 30 are disposed inside the reaction vessel 10. FIG. 2 is a schematic diagram illustrating an example of the arrangement of the multiple light sources 30 in the batch culture apparatus 1a. This diagram illustrates the axis 20 and the multiple light sources 30 as viewed from the z direction in which the axis 20 extends. As shown in FIG. 2, the multiple light sources 30 include a first light source 31 and a second light source 32. In FIG. 2, the angle θ1 formed between the first line L1 and the second line L2 in a plane perpendicular to the z direction satisfies the condition 90°<θ1≦180°. The first straight line L1 is a line connecting the center C1 of the first light source 31 and the center C0 of the axis 20 when viewed from the z direction. The second straight line L2 is a line connecting the center C2 of the second light source 32 and the center C0 of the axis 20 when viewed from the z direction. Each of the multiple light sources 30 may be cylindrical. The center of each of the multiple light sources 30 may include the center of the bottom surface of the cylinder and / or the center of the top surface of the cylinder, and may be included in a line parallel to the Z axis. The angle θ1 may be the angle formed by a plane including the center C1 and the axis 20 and a plane including the center C2 and the axis 20.

[0017] The number and arrangement of the multiple light sources 30 are not limited to a specific embodiment as long as the first light source 31 and the second light source 32 satisfy the condition 90°<θ≦180°. As shown in FIG. 2, the number of the multiple light sources 30 is, for example, 10. FIGS. 3, 4, 5, and 6 each schematically show another example of the arrangement of the multiple light sources 30 in the batch culture apparatus 1a. As shown in FIG. 3, the number of the multiple light sources 30 may be 8. As shown in FIG. 4, the number of the multiple light sources 30 may be 6. As shown in FIG. 5, the number of the multiple light sources 30 may be 4. As shown in FIG. 6, the number of the multiple light sources 30 may be 2. The number of the multiple light sources 30 may be 3, 5, 7, 9, 11, or more. The number of the multiple light sources 30 is, for example, 48 or less.

[0018] FIG. 7 is a diagram schematically showing the arrangement of multiple light sources in a batch culture apparatus 1x according to a comparative example. The batch culture apparatus 1x is configured similarly to the batch culture apparatus 1a, except for parts that will be particularly described. The batch culture apparatus 1x includes only one light source 30 as a light source. FIG. 8 is a diagram schematically showing a batch culture apparatus 1y according to another comparative example. The batch culture apparatus 1y is configured similarly to the batch culture apparatus 1a, except for parts that will be particularly described. The batch culture apparatus 1y includes only one light source, a light source 35, arranged above the reaction tank 10.

[0019] The batch culture apparatuses 1x and 1y each have one light source. If these batch culture apparatuses are scaled for commercial use, adjusting the light intensity of the light source 30 or 35 makes it difficult to widen the range in the culture solution contained in the reaction tank 10 over which light from the light source 30 or 35 reaches with the desired light intensity. On the other hand, in the batch culture apparatus 1a, the multiple light sources 30 include a first light source 31 and a second light source 32 that satisfy the condition 90° < θ1 ≦ 180°. Therefore, even if the batch culture apparatus 1a is configured on a scale suitable for commercial use, light from the multiple light sources 30 can easily reach a wide range of the culture solution of photosynthetic microorganisms contained in the reaction tank 10 with the desired light intensity. This tends to increase the efficiency of photosynthetic microorganism cultivation.

[0020] Photosynthetic microorganisms are not limited to specific photosynthetic microorganisms. Examples of photosynthetic microorganisms include cyanobacteria. Cyanobacteria, also known as blue-green algae or blue-green bacteria, are a group of prokaryotes that perform photosynthesis by capturing light energy with chlorophyll and using the energy obtained to split water and generate oxygen. Cyanobacteria are highly diverse, and in terms of cell shape, there are unicellular species such as Synechocystis sp. PCC 6803 and filamentous species with linked multicellular structures such as Anabaena sp. PCC 7120. Regarding habitats, there are thermophilic species such as Thermosynechococcus elongatus, marine species such as Synechococcus elongatus, and freshwater species such as Synechocystis. There are also many species with unique characteristics, such as Microcystis aeruginosa, which has gas vesicles and produces toxins, and Gloeobacter violaceus, which does not have thylakoids but has proteins called phycobilisomes, which act as light-harvesting antennae, in the plasma membrane.

[0021] The angle θ1 preferably satisfies the condition 105°≦θ1≦180°, more preferably 120°≦θ1≦180°, and even more preferably 135°≦θ1≦180°. The angle θ1 particularly preferably satisfies the condition 150°≦θ1≦180°, and especially preferably 165°≦θ1≦180°.

[0022] 2 to 6 , the plurality of light sources 30 includes, for example, a light source group 33. The light source group 33 includes light sources 30 arranged rotationally symmetrically around the axis 20 when the axis 20 and the plurality of light sources 30 are viewed along the axis 20. With this configuration, light from the plurality of light sources 30 can more easily reach a wide range of the culture solution for photosynthetic microorganisms contained in the reaction tank 10 with a desired amount of light. This tends to increase the efficiency of culturing photosynthetic microorganisms.

[0023] The plurality of light sources 30 includes, for example, two light source groups 33. Each light source group 33 includes light sources 30 arranged at positions that are two-fold or four-fold rotationally symmetric around the axis 20 when the axis 20 and the plurality of light sources 30 are viewed along the axis 20.

[0024] The reaction tank 10 is not limited to a specific tank as long as it can accommodate a culture solution for photosynthetic microorganisms. The reaction tank 10 has, for example, pressure resistance. When photosynthetic microorganisms are cultured by batch operation, the inside of the reaction tank 10 needs to be sterilized before the photosynthetic microorganisms are cultured. This sterilization can be performed by placing the inside of the reaction tank 10 in a pressure state higher than atmospheric pressure. Therefore, if the reaction tank 10 has pressure resistance, the inside of the reaction tank 10 can be easily sterilized, which tends to increase the efficiency of photosynthetic microorganism culture. The reaction tank 10 can be used at a pressure of, for example, 0.2 MPa or more.

[0025] The inner surface of the reaction vessel 10 is made of, for example, metal. The inner surface of the reaction vessel 10 may be a mirror surface. In this case, the light emitted from the plurality of light sources 30 is more likely to be effectively used for culturing photosynthetic microorganisms, and the efficiency of culturing photosynthetic microorganisms is more likely to be increased.

[0026] The side surface 11 inside the reaction tank 10 is, for example, a cylindrical surface. The side surface 11 inside the reaction tank 10 may be a cylindrical surface. The position of the axis 20 inside the reaction tank 10 may be the center of the interior of the reaction tank 10 in a plane perpendicular to the axis 20, or may be shifted from the center. For example, when the side surface 11 inside the reaction tank 10 is a cylindrical surface, the distance between the center of the interior of the reaction tank 10 and the center C0 of the axis 20 is 10% or less of the inner diameter of the reaction tank 10.

[0027] The reaction vessel 10 has a volume of, for example, 0.4 m 3 Thus, even if the reactor 10 has a commercial scale, the efficiency of culturing photosynthetic microorganisms tends to be high because the plurality of light sources 30 includes the first light source 31 and the second light source 32 that satisfy the condition of 90°<θ1≦180°, as described above. The internal volume of the reactor 10 is, for example, 0.45 m 3 or more, 0.5 m 3 More than 1.0m 3 or more, or 2.0 m3 The internal volume of the reaction vessel 10 may be, for example, 5 m 3 The following is the result.

[0028] As shown in FIG. 1 , the shaft 20 extends, for example, from outside the reaction tank 10 through the upper wall of the reaction tank 10 to near the bottom of the reaction tank 10. The shaft 20 is made of, for example, metal. When photosynthetic microorganisms are cultured, the shaft 20 is stationary. For example, an agitator blade (not shown) can be attached to the shaft 20. In addition, the shaft 20 can be connected to a motor (not shown) outside the reaction tank 10. For example, when cleaning the inside of the reaction tank 10, an agitator blade is attached to the shaft 20, and the shaft 20 is connected to the motor. This allows the cleaning solution to be agitated when cleaning the inside of the reaction tank 10, and the reaction tank 10 can be cleaned efficiently.

[0029] 2 , the plurality of light sources 30 includes a light source 30 disposed at a first position P1 when viewing the axis 20 and the plurality of light sources 30 along the axis 20. A distance D1 between the side surface 11 of the reaction vessel 10 and the first position P1 is shorter than a distance D2 between the center of the axis 20 and the first position P1. With this configuration, light from the light source 30 can easily reach the desired amount of light even near the side surface 11 of the reaction vessel 10, which tends to increase the efficiency of culturing photosynthetic microorganisms.

[0030] The first position P1 preferably satisfies the condition D1≦(D1+D2) / 3. With this configuration, the desired amount of light from the light source 30 can reach the reaction vessel 10 even near the side surface 11, which tends to increase the efficiency of culturing photosynthetic microorganisms. The first position P1 satisfies, for example, the condition (D1+D2) / 10≦D1.

[0031] For example, when viewing the axis 20 and the multiple light sources 30 along the axis 20, the first light source 31 is disposed at a position where the distance between the side surface 11 of the reaction vessel 10 and the first light source 31 is shorter than the distance between the center of the axis 20 and the first light source 31. In addition, the second light source 32 is disposed at a position where the distance between the side surface 11 of the reaction vessel 10 and the second light source 32 is shorter than the distance between the center of the axis 20 and the second light source 32. This configuration tends to increase the efficiency of culturing photosynthetic microorganisms. The distance between the side surface 11 and the first light source 31 and the distance between the center of the axis 20 and the first light source 31 may satisfy the same conditions as the distances D1 and D2. The distance between the side surface 11 and the second light source 32 and the distance between the center of the axis 20 and the second light source 32 may satisfy the same conditions as the distances D1 and D2.

[0032] As shown in FIG. 1 , for example, when the interior of the reaction vessel 10 is filled with liquid having a volume of 60% to 90% of the internal volume of the reaction vessel 10, a liquid level L is formed by this liquid. As shown in FIG. 1 , the multiple light sources 30 include, for example, a light source 30 disposed between the liquid level L and the bottom surface of the reaction vessel 10. In culturing photosynthetic microorganisms, the interior of the reaction vessel 10 can contain a culture solution having a volume of 60% to 90% of the internal volume of the reaction vessel 10. Therefore, by including the multiple light sources 30 disposed between the liquid level L and the bottom surface of the reaction vessel 10, light from the multiple light sources 30 can easily reach a wide range of the culture solution at the desired light intensity. As a result, the efficiency of culturing photosynthetic microorganisms is likely to be higher.

[0033] As described above, for example, when the inside of the reaction vessel 10 is filled with liquid whose volume is 60% to 90% of the internal volume of the reaction vessel 10, the area of ​​the light-emitting surfaces of the plurality of light sources 30 that contact the liquid is at least half of the total area of ​​the light-emitting surfaces. With this configuration, light from the plurality of light sources 30 can easily reach a wide range of the culture solution contained inside the reaction vessel 10 with a desired amount of light. As a result, the efficiency of culturing photosynthetic microorganisms can be improved.

[0034] The shape of the light source 30 is not limited to a specific shape. For example, the light source 30 extends along the axis 20. With this configuration, light from the multiple light sources 30 can easily reach a wide range of the culture solution contained inside the reaction tank 10 with a desired amount of light. As a result, the efficiency of culturing photosynthetic microorganisms can be improved.

[0035] The light emitting surface of the light source 30 is, for example, a cylindrical surface, and may also be a circular cylindrical surface.

[0036] The wavelength λ of the light emitted from the light source 30 is not limited to a specific value. The wavelength λ is, for example, 400 nm or more and 700 nm or less. In this case, the efficiency of culturing photosynthetic microorganisms tends to be higher.

[0037] 1 , the batch culture apparatus 1a further includes, for example, a fixture 22. The fixture 22 is attached to the shaft 20. The plurality of light sources 30 are suspended from the fixture 22. With this configuration, the plurality of light sources 30 can be easily positioned at desired positions by the fixture 22. Furthermore, for example, when cleaning and sterilizing the interior of the reaction tank 10, the plurality of light sources 30 can be easily removed from the reaction tank 10 together with the fixture 22.

[0038] Fig. 9 is a plan view showing the fixture 22 of the batch culture apparatus 1a. As shown in Fig. 9, the fixture 22 includes a clamp 22c that can be attached to and detached from the shaft 20, and a rod 22s. The rod 22s extends from the clamp 22c toward the side surface 11 of the reaction tank 10 when the clamp 22c is fixed to the shaft 20. This configuration makes it easy to place multiple light sources 30 inside the reaction tank 10 and to remove the multiple light sources 30 from the reaction tank 10.

[0039] The rod 22s may be detachable from the clamp 22c. In this case, for example, by replacing only the rod 22s, it is possible to change the number and arrangement of the multiple light sources 30 in the reaction vessel 10 to suit the reaction vessel 10. The rod 22s may be configured integrally with the clamp 22c.

[0040] 1, the batch culture apparatus 1a further includes, for example, a temperature regulator 50. The temperature regulator 50 is disposed along the inner surface of the reaction tank 10 and regulates the temperature of the culture solution. With this configuration, it is easy to regulate the temperature of the culture solution in the batch culture apparatus 1a to a temperature suitable for culturing photosynthetic microorganisms.

[0041] The temperature regulator 50 adjusts the absolute value of the difference between the optimum temperature for growth of photosynthetic microorganisms and the temperature of the culture solution contained in the reaction tank 10 to, for example, 5° C. or less. This makes it easier to increase the efficiency of photosynthetic microorganism cultivation in the batch culture apparatus 1a.

[0042] 1, the temperature regulator 50 is disposed, for example, surrounding the outer surface of the reaction tank 10. With such a configuration, the temperature of the culture solution contained in the reaction tank 10 tends to be uniform, which tends to increase the efficiency of culturing photosynthetic microorganisms.

[0043] As described above, the light source 30 extends, for example, along the axis 20. The temperature regulator 50 overlaps the light source 30, for example, in a direction parallel to the axis 20. Such a configuration tends to result in higher efficiency in culturing photosynthetic microorganisms.

[0044] The temperature regulator 50 is configured by, for example, a water jacket, or may be an electric heater.

[0045] 1, the batch culture apparatus 1a further includes, for example, an air vent 40. The air vent 40 guides air to the lower part of the reaction tank 10 and discharges air from the upper part of the reaction tank 10. With this configuration, air is introduced into the lower part of the reaction tank 10, which tends to further increase the efficiency of culturing photosynthetic microorganisms.

[0046] The batch culture apparatus 1a includes, for example, a supply pipe 41 and a discharge pipe 42 that form an air passage 40. The supply pipe 41 extends from the outside of the reaction tank 10 to the inside of the reaction tank 10, and one end of the supply pipe 41 located inside the reaction tank 10 forms a supply port. The discharge pipe 42 connects the inside of the reaction tank 10 to the outside of the reaction tank 10. The discharge pipe 42 has one end that contacts the inside of the reaction tank 10, and this end forms a discharge port.

[0047] The batch culture apparatus 1a can be modified from various viewpoints. For example, the batch culture apparatus 1a may be modified as shown in the batch culture apparatus 1b illustrated in FIG. 10 and the batch culture apparatus 1c illustrated in FIG. 11. FIG. 10 is a diagram schematically illustrating another example of the batch culture apparatus of the present disclosure, and FIG. 11 is a diagram schematically illustrating yet another example of the batch culture apparatus of the present disclosure. The batch culture apparatuses 1b and 1c illustrated in FIG. 10 are configured similarly to the batch culture apparatus 1a, except for portions that will be particularly described. The components of the batch culture apparatuses 1b and 1c that correspond to the components of the batch culture apparatus 1a are denoted by the same reference numerals, and detailed description thereof will be omitted. The description of the batch culture apparatus 1a also applies to the batch culture apparatuses 1b and 1c, unless technically inconsistent.

[0048] 10, in the batch culture apparatus 1b, the light source 30 is spherical. In this case, the multiple light sources 30 include the first light source 31 and the second light source 32 that satisfy the condition of 90°<θ1≦180°, which tends to increase the efficiency of culturing photosynthetic microorganisms.

[0049] In the batch culture apparatus 1 b, a plurality of spherical light sources 30 may be arranged in a direction parallel to the axis 20 .

[0050] As shown in Figure 11, the batch culture apparatus 1c is provided with, for example, a protrusion 25 that protrudes from the inner side surface 11 of the reaction tank 10 toward the center of the interior of the reaction tank 10. A plurality of light sources 30 are suspended from the protrusion 25. This allows the plurality of light sources 30 to be positioned at desired positions. The batch culture apparatus 1c is not provided with, for example, a shaft 20. The batch culture apparatus 1c may be provided with a shaft 20.

[0051] (Additional Note) From the above description, the following techniques are disclosed.

[0052] (Technology 1) A batch culture device comprising: a reaction tank capable of accommodating a culture solution for photosynthetic microorganisms; an axis extending along the side surface of the reaction tank at the center of the reaction tank; and a plurality of light sources arranged inside the reaction tank, wherein the plurality of light sources include a first light source and a second light source; the direction in which the axis extends is the z direction, and an angle θ1 formed in a plane perpendicular to the z direction by a first line that is a line connecting the center of the first light source and the center of the axis when viewed from the z direction, and a second line that is a line connecting the center of the second light source and the center of the axis when viewed from the z direction, satisfies the condition of 90°<θ1≦180°.

[0053] (Technology 2) The batch culture apparatus according to claim 1, wherein the plurality of light sources includes a light source group consisting of a plurality of light sources arranged rotationally symmetrically around the axis when the axis and the plurality of light sources are viewed along the axis.

[0054] (Technology 3) The batch culture apparatus according to Technology 1 or 2, wherein the photosynthetic microorganism is a cyanobacterium.

[0055] (Technology 4) The batch culture apparatus according to any one of Techniques 1 to 3, wherein the reaction vessel has pressure resistance.

[0056] (Technology 5) The batch culture apparatus according to any one of Technologies 1 to 4, wherein the plurality of light sources includes a light source arranged at a first position when the axis and the plurality of light sources are viewed along the axis, and a distance between the side surface of the reaction vessel and the first position is shorter than a distance between a center of the axis and the first position.

[0057] (Technology 6) The batch culture apparatus according to any one of Technologies 1 to 5, wherein the plurality of light sources include a light source that is arranged between a liquid level formed by the liquid and a bottom surface of the reaction tank when the inside of the reaction tank is filled with the liquid having a volume of 60% to 90% of the internal volume of the reaction tank.

[0058] (Technology 7) The batch culture apparatus according to any one of Technologies 1 to 6, wherein when the inside of the reaction tank is filled with a liquid having a volume of 60% to 90% of the internal volume of the reaction tank, the area of ​​the light-emitting surfaces of the plurality of light sources that contact the liquid is half or more of the total area of ​​the light-emitting surfaces.

[0059] (Technology 8) The batch culture apparatus according to any one of Technologies 1 to 7, wherein the light source extends along the axis.

[0060] (Technology 9) The batch culture apparatus according to any one of Technologies 1 to 8, further comprising a fixture attached to the shaft, wherein the plurality of light sources are suspended from the fixture.

[0061] (Technology 10) The batch culture apparatus according to Technology 9, wherein the fixing device includes a clamp that is detachable from the shaft, and a rod that extends from the clamp toward a side surface of the reaction vessel when the clamp is fixed to the shaft.

[0062] (Technology 11) The batch culture apparatus according to any one of Technologies 1 to 10, further comprising a temperature regulator arranged along the inner surface of the reaction vessel and regulating the temperature of the culture solution.

[0063] (Technology 12) The batch culture apparatus according to Technology 11, wherein the temperature regulator adjusts the absolute value of the difference between the optimum temperature for growth of the photosynthetic microorganism and the temperature of the culture solution to 5°C or less.

[0064] (Technology 13) The batch culture apparatus according to Technology 11 or 12, wherein the temperature regulator is disposed so as to surround the outer surface of the reaction vessel.

[0065] (Technology 14) The light source extends along the axis, and the temperature adjuster overlaps the light source in a direction parallel to the axis.

[0066] The batch culture apparatus according to any one of techniques 11 to 13.

[0067] (Technology 15) The batch culture apparatus according to any one of Techniques 1 to 14, wherein the reaction vessel has an inner surface made of metal or having a mirror finish.

[0068] (Technology 16) The batch culture apparatus according to any one of Techniques 1 to 15, further comprising an air passage that introduces air into a lower portion of the reaction tank and discharges air from an upper portion of the reaction tank.

[0069] (Technology 17) The reaction vessel is 0.4 m 3 17. The batch culture apparatus according to any one of claims 1 to 16, which is capable of accommodating the culture medium.

[0070] (Technology 18) The batch culture apparatus according to any one of Techniques 1 to 17, wherein the light source emits light having a wavelength in the range of 400 nm to 700 nm.

[0071] (Technology 19) A batch culture device comprising: a reaction tank capable of accommodating a culture solution for photosynthetic microorganisms; a plurality of light sources arranged inside the reaction tank; and a protrusion protruding from a side surface of the interior of the reaction tank toward the center of the interior of the reaction tank, wherein the plurality of light sources are suspended from the protrusion, and the plurality of light sources include a first light source and a second light source; a direction parallel to the side surface of the interior of the reaction tank is defined as a z direction, and an angle θ1 formed in a plane perpendicular to the z direction by a first line that is a line connecting the center of the first light source to the center of the interior of the reaction tank when viewed from the z direction, and a second line that is a line connecting the center of the second light source to the center of the interior of the reaction tank when viewed from the z direction, satisfies the condition of 90°<θ1≦180°.

[0072] The present disclosure will be described in more detail below with reference to examples. Note that the following examples are illustrative and the present disclosure is not limited to the following examples.

[0073] <Example> Synechocystis sp. PCC6803 (hereinafter referred to as "Synechocystis"), a cyanobacterial species, was cultured at an initial cell concentration of OD 730 0.4m so that is between 0.02 and 0.05 3 The optimum temperature for growth of Synechocystis is 30°C. Initial cell concentration OD 730is the optical density of the culture medium at a wavelength of 730 nm. The concentrations of each component in the BG-11 medium are shown in Table 1.

[0074]

[0075] 0.5 m 3 The Synechocystis culture solution was placed in a stainless steel SUS304 tank with an internal volume of 1000 liters, and Synechocystis was cultivated while maintaining the internal temperature of the tank at 30°C. The internal temperature of the tank was controlled using a water jacket placed around the tank. A stainless steel SUS304 shaft was placed in the center of the tank. This shaft penetrated the top surface of the tank and extended to near the bottom. Additionally, a fixture as shown in Figure 9 was attached to this shaft. Ten, eight, six, four, or two light sources were suspended from the rod of this fixture, as shown in Figures 2 to 6, and these light sources were arranged rotationally symmetrically around the axis inside the tank. A long white LED underwater fishing light manufactured by Ks Garage was used as the light source. This light source consumed 60 W and was capable of emitting light with a wavelength ranging from 400 nm to 700 nm. When the axis and the multiple light sources were viewed along the axis, the multiple light sources included a pair of light sources positioned such that θ1 = 180°. The inner diameter of the tank was 0.73 m, and the distance between the side of the tank and the light source closest to that side was 0.09 m. In culturing Synechocystis, the light source was illuminated while completely immersed in the culture solution. In culturing Synechocystis, air was introduced through a supply port located near the bottom of the tank and discharged through a discharge port located at the top of the tank. The air supply to the tank was 0.4 m 3 / min.

[0076] Comparative Example 1 As shown in FIG. 7, Synechocystis was cultured in the same manner as in Example, except that only one light source was placed inside the tank.

[0077] Comparative Example 2 Synechocystis was cultured in the same manner as in Example, except for the following points: Instead of the above light source, an LED floodlight Ginga II manufactured by Atsuta Shizai or an LED searchlight (power consumption 320 W) manufactured by Art Pro Co., Ltd. was placed above the culture solution as shown in Figure 8 and emitted light. Only one light source was used in the culture of Synechocystis.

[0078] (Specific Growth Rate) During the cultivation of Synechocystis, the optical density (OD) of the culture solution at a wavelength of 730 nm was measured. 730 The OD was measured at the start of the culture and one day after the start of the culture, and the specific growth rate μ [ / day] of Synechocystis was determined according to the following formula (1). 730 _0 is the optical density at a wavelength of 730 nm of the culture solution at the start of culturing Synechocystis, and OD 730 _ 1 is the optical density at a wavelength of 730 nm of the culture solution after one day of culturing Synechocystis. μ = ln(OD 730 _1-OD 730 _0) Formula (1)

[0079] Fig. 12 is a graph showing the relationship between the specific growth rate of Synechocystis and the number of light sources placed inside the tank in the above-mentioned Synechocystis culture. As shown in Fig. 12, by placing two or more light sources in predetermined positions and emitting light while completely immersed in the culture solution, the specific growth rate μ becomes 0.6 [ / day] or more, and the efficiency of Synechocystis culture is high. On the other hand, when only one light source is used, as in Comparative Examples 1 and 2, the specific growth rate μ becomes less than 0.6 [ / day], and it is difficult to say that the efficiency of Synechocystis culture is high.

[0080] According to the present disclosure, it is possible to produce substances by culturing photosynthetic microorganisms on a commercial scale.

[0081] 1a, 1b, 1c Batch culture apparatus 10 Reaction tank 11 Side surface 20 Shaft 22 Fixing tool 22c Clamp 22s Rod 25 Protrusion 30 Light source 31 First light source 32 Second light source 33 Light source group 40 Ventilation path 50 Temperature regulator L1 First straight line L2 Second straight line

Claims

1. A batch culture apparatus comprising: a reaction tank capable of containing a culture solution for photosynthetic microorganisms; an axis extending along the side surface of the reaction tank at the center of the inside of the reaction tank; and a plurality of light sources arranged inside the reaction tank, wherein the plurality of light sources include a first light source and a second light source, the direction in which the axis extends is the z direction, and an angle θ1 formed by a first line which is a line connecting the center of the first light source and the center of the axis when viewed from the z direction and a second line which is a line connecting the center of the second light source and the center of the axis when viewed from the z direction, in a plane perpendicular to the z direction, satisfies the condition of 90°<θ1≦180°.

2. The batch culture apparatus according to claim 1, wherein the plurality of light sources includes a light source group consisting of a plurality of light sources arranged rotationally symmetrically around the axis when the axis and the plurality of light sources are viewed along the axis.

3. The batch culture apparatus according to claim 1, wherein the photosynthetic microorganism is a cyanobacterium.

4. The batch culture apparatus according to claim 1, wherein the reaction tank has pressure resistance.

5. The batch culture apparatus of claim 1, wherein the plurality of light sources includes a light source disposed at a first position when the axis and the plurality of light sources are viewed along the axis, and a distance between the side surface of the reaction vessel and the first position is shorter than a distance between a center of the axis and the first position.

6. The batch culture apparatus according to claim 1, wherein the plurality of light sources include a light source disposed between a liquid level formed by the liquid and a bottom surface of the reaction tank when the inside of the reaction tank is filled with liquid having a volume of 60% or more and 90% or less of the internal volume of the reaction tank.

7. The batch culture apparatus according to claim 1, wherein when the inside of the reaction tank is filled with liquid having a volume of 60% or more and 90% or less of the internal volume of the reaction tank, the area of ​​the light-emitting surfaces of the multiple light sources that contact the liquid is more than half of the total area of ​​the light-emitting surfaces.

8. The batch culture apparatus of claim 1, wherein the light source extends along the axis.

9. The batch incubation apparatus of claim 1, further comprising a fixture attached to said shaft, said plurality of light sources being suspended from said fixture.

10. The batch culture apparatus according to claim 9, wherein the fixing device includes a clamp that is detachable from the shaft, and a rod that extends from the clamp toward a side surface of the reaction tank when the clamp is fixed to the shaft.

11. The batch culture apparatus according to claim 1, further comprising a temperature regulator arranged along the inner surface of the reaction vessel for regulating the temperature of the culture solution.

12. The batch culture apparatus according to claim 11, wherein the temperature regulator adjusts the absolute value of the difference between the optimum temperature for growth of the photosynthetic microorganism and the temperature of the culture solution to 5° C. or less.

13. The batch culture apparatus according to claim 11, wherein the temperature regulator is disposed surrounding the outer surface of the reaction vessel.

14. The batch culture apparatus according to claim 11, wherein the light source extends along the axis, and the temperature regulator overlaps the light source in a direction parallel to the axis.

15. The batch culture apparatus according to claim 1, wherein the reaction vessel has an inner surface made of metal or having a mirror finish.

16. The batch culture apparatus according to claim 1, further comprising an air passage for introducing air into a lower portion of the reaction tank and discharging air from an upper portion of the reaction tank.

17. The reactor is 0.4 m 3 The batch culture apparatus according to claim 1 , capable of accommodating the above culture solution.

18. The batch culture apparatus according to claim 1, wherein the light source emits light having a wavelength in the range of 400 nm or more and 700 nm or less.

19. A batch culture apparatus comprising: a reaction tank capable of containing a culture solution for photosynthetic microorganisms; a plurality of light sources arranged inside the reaction tank; and a protrusion protruding from a side surface of the interior of the reaction tank toward the center of the interior of the reaction tank, the plurality of light sources being suspended from the protrusion, the plurality of light sources including a first light source and a second light source, a direction parallel to the side surface of the interior of the reaction tank being the z direction, and an angle θ1 formed in a plane perpendicular to the z direction by a first line which is a line connecting the center of the first light source to the center of the interior of the reaction tank when viewed from the z direction, and a second line which is a line connecting the center of the second light source to the center of the interior of the reaction tank when viewed from the z direction, satisfies the condition of 90° < θ1 ≦ 180°.

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