Culture apparatus and culture method

Abstract

To provide a culture apparatus and a culture method in which a shape change of a housing part associated with liquid pressure change of storage liquid can be suppressed, and microalgae can be efficiently cultured.SOLUTION: A culture apparatus 10 comprises: a translucent liquid storage part 12 capable of storing storage liquid W; a housing part 14 which is arranged inside the liquid storage part 12, and capable of housing culture solution L and microalgae; and a frame member 46 arranged inside the liquid storage part 12. A side face 14S of the housing part 14 is regulated by the frame member 46. In a culture method, microalgae are cultured in the housing part 14 while regulating the side face 14S of the housing part 14 by the frame member 46 arranged inside the liquid storage part 12.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a culture device and a culture method for culturing microalgae.

Background Art

[0002] Conventionally, efforts aimed at mitigating or reducing the impact of climate change have been continued, and research and development regarding reduction of carbon dioxide emissions have been conducted towards this realization. A culture device for culturing microalgae is expected to contribute to mitigating or reducing the impact of climate change.

[0003] For example, in the culture device (photobioreactor) disclosed in Patent Document 1, a ballast chamber is provided at the lower end of a culture chamber made of a flexible material (film material) in order to maintain the photobioreactor in a vertical position in water, and a buoyancy chamber is provided at the upper end of the culture chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A culture chamber (accommodation part) made of a flexible material is liable to deform. If the shape in the thickness direction of the accommodation part cannot be maintained well, the culture efficiency of microalgae may decrease.

[0006] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0007] A first aspect of the present invention is a culture apparatus for culturing microalgae in a culture medium, comprising: a translucent liquid storage section capable of storing a liquid; a storage section disposed inside the liquid storage section and capable of containing the culture medium and the microalgae; and a frame member disposed inside the liquid storage section, wherein the side surface of the storage section is restricted by the frame member.

[0008] A second aspect of the present invention is a culture method for culturing microalgae in a culture medium, wherein a liquid is stored inside a translucent liquid storage section, the culture medium and the microalgae are contained inside a containment section located inside the liquid storage section, and the microalgae are cultivated inside the containment section while the sides of the containment section are restricted by a frame member located inside the liquid storage section. [Effects of the Invention]

[0009] According to the present invention, since the position of the side surface of the containment section is restricted by the frame member, changes in the shape of the containment section due to changes in the liquid pressure of the stored liquid can be suppressed. By suppressing changes in the shape of the containment section with the frame member and cultivating microalgae within the containment section, microalgae can be cultivated efficiently. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a front cross-sectional view of a culture apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 is a side cross-sectional view of the culture apparatus. [Figure 3] Figure 3 is a plan view of the culture apparatus. [Figure 4] Figure 4 is a perspective view of the fixing member attached to the side of the housing. [Modes for carrying out the invention]

[0011] The culture apparatus 10 according to this embodiment, shown in Figure 1, cultivates microalgae in a culture medium L containing water by supplying light and gas G to the microalgae. Examples of gas G supplied to the culture apparatus 10 include carbon dioxide gas or a carbon dioxide-containing gas (e.g., air). As a result, the microalgae grow in the culture apparatus 10 while performing photosynthesis. In other words, the culture apparatus 10 cultivates microalgae. It is preferable that the culture medium L contains, in addition to water, nutrients necessary for the cultivation of microalgae (e.g., at least one selected from nitrogen, phosphorus, and potassium). It is preferable that gas G contains, for example, carbon dioxide gas emitted from a factory.

[0012] The microalgae that can be cultured using the culture device 10 are not particularly limited. When using the cultured microalgae to produce biofuels such as ethanol, it is preferable to culture microalgae classified into the Green Algae (e.g., Chlamydomonas and Chlorella), Prasinophyceae, Cryptofophyceae and Cyanobacteria (e.g., Spirulina) using the culture device 10. An example of a suitable microalgae to be cultured using the culture device 10 is the "HondaDREAMO strain" (deposit date April 22, 2016, accession number FERM BP-22306), which has been deposited with the National Institute of Technology and Evaluation Patent Organism Depositary Center (Room 120, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture).

[0013] The culture apparatus 10 is installed in an environment where the microalgae can be irradiated with light of wavelengths necessary for their growth (e.g., 400-700 nm). Such an environment could be, for example, outdoors where sunlight can be irradiated onto the microalgae. However, the culture apparatus 10 may also be installed indoors where sunlight can be irradiated onto the microalgae. Alternatively, the culture apparatus 10 may also be installed indoors where artificial light of the above wavelengths can be irradiated onto the microalgae.

[0014] In the following, the orientation of each component of the culture device 10 will be explained based on the case where the culture device 10 is installed in the location where microalgae are cultured, as shown in Figure 1.

[0015] The culture apparatus 10 comprises a translucent liquid storage section 12 capable of storing the storage liquid W, and a storage section 14 capable of containing the microalgae solution (culture liquid L and microalgae). The liquid storage section 12 is a bag-shaped container made of a flexible and translucent material. Examples of materials used for the liquid storage section 12 include linear low-density polyethylene (LLDPE). The liquid storage section 12 is formed, for example, by folding a strip-shaped sheet made of a single flexible material in half and welding both ends in the width direction, thereby closing the lower end into a bag shape. An opening 12a is formed at the upper end of the liquid storage section 12.

[0016] The liquid storage section 12 is capable of storing liquid W supplied from a liquid storage supply mechanism (not shown). The liquid storage W is a translucent liquid, such as water. In this embodiment, since the liquid storage W is water, the liquid storage section 12 is a water storage tank.

[0017] As shown in Figure 2, the liquid storage section 12 is arranged along the vertical direction. That is, the liquid storage section 12 is positioned in an upright position. The liquid storage section 12 has a first side wall 121 and a second side wall 122 that face each other.

[0018] To position the liquid reservoir 12 in an upright position, the culture apparatus 10 further comprises a liquid tank frame 16 that supports the liquid reservoir 12. The liquid tank frame 16 comprises a lower frame 160, a first lateral frame 161 extending upward from one end of the lower frame 160, and a second lateral frame 162 extending upward from the other end of the lower frame 160. The first lateral frame 161 and the second lateral frame 162 extend parallel to each other with a horizontal gap between them.

[0019] A plurality of first side frames 161 are arranged at intervals in the horizontal direction in the width direction of the culture device 10 (the X direction in FIG. 1) so as not to prevent light from entering the liquid storage part 12 and the storage part 14. At the upper end of the first side frame 161, a first fixed bar 163 extending along the horizontal direction in the width direction of the culture device 10 is provided. At the upper end of the second side frame 162, a second fixed bar 164 extending parallel to the first fixed bar 163 is provided. The upper end of the liquid storage part 12 (the part forming the opening 12a) is folded outward and fixed to the first fixed bar 163 and the second fixed bar 164.

[0020] The storage part 14 is arranged inside the liquid storage part 12. Microalgae are cultured in the storage part 14. That is, the storage part 14 constitutes a culture tank in the culture device 10. The microalgae liquid stored in the storage part 14 is a fluid containing the microalgae cultured in the storage part 14 and the culture solution L used for culturing the microalgae. Note that the microalgae liquid may contain, for example, polysaccharides produced by the microalgae and released outside the microalgae.

[0021] The storage part 14 is a bag-shaped container made of a material having flexibility and light transmittance. Examples of the constituent material of the storage part 14 include linear low-density polyethylene (LLDPE). The storage part 14 is formed in a bag shape with a closed lower end, for example, by folding a strip-shaped sheet material made of a single flexible material in half and welding both end portions in the width direction. An opening 14a is formed at the upper end portion 14U of the storage part 14. The storage part 14 has a first side wall 141 and a second side wall 142 facing each other.

[0022] As shown in FIG. 1, the culture device 10 further includes a gas supply pipe 32 and a plurality of guide parts 36. The gas supply pipe 32 is arranged at the lower end portion 14L of the storage part 14 which is a culture tank. Specifically, the gas supply pipe 32 is arranged at the bottom 143 of the storage part 14. The gas supply pipe 32 is a mechanism for supplying the above-described gas G into the storage part 14.

[0023] The gas supply pipe 32 extends horizontally along the width direction (X direction) of the housing section 14 at the bottom 143 of the housing section 14. The specific gravity of the gas supply pipe 32 is sufficiently greater than the specific gravity of the culture medium L. Therefore, the gas supply pipe 32 sinks into the bottom 143 of the housing section 14 by its own weight, pushing the bottom 143 downward. The gas supply pipe 32 may be fixed to the bottom 143 of the housing section 14 by adhesive or welding.

[0024] A gas supply tube 40 is connected to one end 321 of the gas supply pipe 32 in the direction of its extension. The gas supply tube 40 extends along one end in the width direction of the housing 14 and extends to the outside of the housing 14 through the opening 14a of the housing 14. Gas G is supplied to the gas supply pipe 32 via the gas supply tube 40. The other end 322 of the gas supply pipe 32 in the direction of its extension is closed.

[0025] The gas supply pipe 32 has a plurality of gas supply ports 33 that are spaced apart in the direction of extension of the gas supply pipe 32. The plurality of gas supply ports 33 are positioned to correspond to the plurality of guide sections 36 and supply gas G toward the plurality of guide sections 36. That is, the plurality of gas supply ports 33 are positioned facing the plurality of guide sections 36. In Figure 1, four gas supply ports 33 are provided. Note that the number of gas supply ports 33 is the same as the number of guide sections 36, and therefore increases or decreases according to the number of guide sections 36.

[0026] The multiple guide sections 36 are a mechanism that works in cooperation with the gas G supplied from the gas supply pipe 32 to generate a liquid flow F (convection) in the culture medium L inside the containment section 14. Specifically, when gas G is supplied into each guide section 36, it discharges the culture medium L to the outside of the guide section 36 and draws the culture medium L into the inside of the guide section 36, thereby generating a liquid flow F of the culture medium L inside the containment section 14. The multiple guide sections 36 are arranged at intervals in the width direction of the containment section 14.

[0027] Each guide section 36 is a tubular member having a flow path inside. Each guide section 36 has a suction port 361 that draws the culture medium L from the outside to the inside of the guide section 36 when gas G is supplied, and a discharge port 362 that discharges the culture medium L from the inside to the outside of the guide section 36. Each guide section 36 has a guide body section 363 that extends along the depth direction (Z direction) of the housing section 14, and a direction changing section 364 that is bent from the upper end of the guide body section 363 in a direction intersecting the depth direction of the housing section 14. The direction changing sections 364 of multiple guide sections 36 are all facing the same direction.

[0028] A suction port 361 is formed at the lower end of the guide body 363. The suction port 361 is spaced upward from the bottom 143 of the housing 14. Therefore, a flow path is secured between the bottom 143 of the housing 14 and the suction port 361 of the guide 36 through which the culture medium L can flow. The multiple suction ports 361 each face the multiple gas supply ports 33 of the gas supply pipe 32. A discharge port 362 is formed at the tip of the direction changing section 364.

[0029] Gas G discharged from the gas supply port 33 of the gas supply pipe 32 is introduced into the guide section 36 via the suction port 361. Gas G rises within the guide section 36 due to buoyancy and is discharged to the outside of the guide section 36 via the discharge port 362. This allows gas G to dissolve in the culture medium L within the containment section 14 and generates a liquid flow F (convection) circulating within the containment section 14. The liquid flow F allows the microalgae circulating with the culture medium L to be well dispersed within the containment section 14, enabling efficient growth of the microalgae.

[0030] Each guide section 36 is supported by a guide support section 42. As shown in Figure 2, the guide support section 42 has a horizontal bar 421 and a vertical bar 422 and is configured in a T-shape. The horizontal bar 421 rests on the upper end of the liquid tank frame 16, straddling the first fixing bar 163 and the second fixing bar 164 of the liquid tank frame 16, along the thickness direction (Y direction) of the liquid storage section 12 and the storage section 14. The vertical bar 422 extends downward from the longitudinal center of the horizontal bar 421. The upper end of the guide section 36 is connected to the lower end of the vertical bar 422.

[0031] The culture apparatus 10 further comprises a frame member 46 positioned inside the liquid storage section 12. The side surfaces 14S (first side wall 141 and second side wall 142) of the containment section 14 are restricted by the frame member 46. The frame member 46 supports the containment section 14 inside the liquid storage section 12. The frame member 46 is fixed to the upper end of the liquid tank frame 16 and extends downward from the upper end of the liquid storage section 12 inside the liquid storage section 12. The frame member 46 is a wire-like (linear) member and is made of, for example, a resin material or a metal material.

[0032] Specifically, the frame member 46 has a frame body portion 461 configured in a roughly U-shape that is convex downwards, and a pair of hook portions 462 provided at the upper end of the frame body portion 461. The housing portion 14 is positioned inside the roughly U-shaped frame body portion 461. The first side wall 141, the second side wall 142, and the lower end portion 14L of the housing portion 14 are supported by the frame body portion 461 along the frame body portion 461. The pair of hook portions 462 curve outwards from the upper end of the frame body portion 461 in the thickness direction (Y direction) of the housing portion 14 and hook onto the first fixing bar 163 and the second fixing bar 164 of the liquid tank frame 16, respectively. As a result, the frame member 46 is supported at the upper end of the liquid tank frame 16.

[0033] With the frame member 46 supported at the upper end of the liquid tank frame 16 and the storage section 14 supported by the frame member 46, the lower end of the frame member 46 and the lower end 14L of the storage section 14 are spaced apart from the bottom 123 of the liquid storage section 12. In other words, the lower end of the frame member 46 and the lower end 14L of the storage section 14 are located above the bottom 123 of the liquid storage section 12.

[0034] As shown in Figure 3, in this embodiment, the culture apparatus 10 comprises a plurality of frame members 46. The plurality of frame members 46 are arranged at intervals in the width direction (X direction) of the housing section 14. It is preferable that the plurality of frame members 46 are arranged at equal intervals.

[0035] Fixing members 48 made of a flexible material are welded to the side surfaces 14S (first side wall 141 and second side wall 142) of the housing section 14. In this embodiment, corresponding to the multiple frame members 46, multiple fixing members 48 are arranged at intervals in the width direction of the housing section 14 on each of the first side wall 141 and the second side wall 142. Each fixing member 48 protrudes outward from the side surface 14S of the housing section 14 in the thickness direction (Y direction) of the housing section 14.

[0036] As shown in Figure 2, multiple fixing members 48 are arranged at intervals in the depth direction (Z direction) of the housing section 14. The fixing members 48 may also be provided at the lower end portion 14L of the housing section 14.

[0037] As shown in Figure 4, the fixing member 48 is formed in an L-shape. The fixing member 48 has a welded surface 481 that extends along the side surface 14S of the housing portion 14, and an engaging piece 482 that protrudes in the thickness direction of the housing portion 14 from one end of the welded surface 481 (the lower end of the welded surface 481 in Figure 4). The welded surface 481 and the side surface 14S of the housing portion 14 are welded together in a planar manner. The engaging piece 482 may protrude from the upper end of the welded surface 481. The engaging piece 482 has an insertion hole 483 through which the frame member 46 is inserted. The frame member 46 is not joined to the insertion hole 483 and can be removed from the insertion hole 483.

[0038] Since the storage section 14 is supported by the frame member 46 as described above, as shown in Figure 2, the shape of the storage section 14 is maintained to conform to the shape of the frame member 46 inside the liquid storage section 12.

[0039] The culture apparatus 10 is used as follows:

[0040] In the culture apparatus 10, a storage liquid W is supplied from a storage liquid supply mechanism (not shown) to the storage liquid section 12, and a culture medium L and microalgae are supplied from a culture medium supply mechanism (not shown) to the containment section 14. As a result, the storage liquid W fills the storage liquid section 12, and the culture medium L and microalgae fill the containment section 14. In Figure 1, gas G is supplied to the containment section 14 from a gas supply pipe 32 provided at the bottom 143 of the containment section 14. As a result, the culture apparatus 10 supplies light and gas G to the microalgae in the culture medium L, and cultivates the microalgae while restricting the side surface 14S of the containment section 14 with a frame member 46.

[0041] This embodiment provides the following effects.

[0042] As shown in Figure 2, the position of the side surface 14S of the containment section 14 is restricted by the frame member 46, which suppresses changes in the shape of the containment section 14 due to changes in the liquid pressure of the stored liquid W. By suppressing changes in the shape of the containment section 14 with the frame member 46, microalgae can be cultured within the containment section 14, allowing for efficient cultivation of microalgae.

[0043] As shown in Figure 4, a fixing member 48 made of a flexible material is welded to the side surface 14S of the housing section 14. The fixing member 48 has an insertion hole 483 through which the frame member 46 is inserted. Since the frame member 46 is inserted through the fixing member 48 welded to the housing section 14, the frame member 46 can be easily removed from the housing section 14, for example, when performing maintenance (cleaning, etc.) on the housing section 14.

[0044] The fixing member 48 has a welded surface 481 that extends along the side surface 14S of the housing portion 14. The welded surface 481 and the side surface 14S of the housing portion 14 are welded together in a planar manner. Because the fixing member 48 is welded to the housing portion 14 in a planar manner, it is possible to prevent the housing portion 14, which is made of a flexible material, from tearing.

[0045] As shown in Figure 2, the frame member 46 is fixed to the upper end of the liquid tank frame 16 and extends downward from the upper end of the liquid storage section 12 through the interior of the liquid storage section 12. Because the frame member 46 is fixed to the liquid tank frame 16, the frame member 46 can be easily fixed without damaging the liquid storage section 12, which is made of a flexible material.

[0046] The culture apparatus 10 is equipped with a gas supply pipe 32 located at the bottom 143 of the containment section 14, and the specific gravity of the gas supply pipe 32 is greater than the specific gravity of the culture medium L. Because the weight of the gas supply pipe 32 pulls the containment section 14 toward the lower end of the liquid storage section 12, the shape of the containment section 14 can be maintained simply by regulating the position of the side surface 14S of the containment section 14. That is, although the weight of the gas supply pipe 32 acts as an inward deformation force F1 on the side surface 14S of the containment section 14, the resistance force F2 of the frame member 46 acts to counteract this deformation force F1, thus maintaining the shape of the containment section 14.

[0047] As shown in Figure 1, multiple guide sections 36 are arranged within the housing section 14. The gas supply pipe 32 has multiple gas supply ports 33 that supply gas G toward the multiple guide sections 36 at positions corresponding to the multiple guide sections 36. Since the gas supply pipe 32 with multiple gas supply ports 33 functions as a collective piping that supplies gas G to the multiple guide sections 36, the structure of the culture apparatus 10 is streamlined (simplified).

[0048] This embodiment allows for the efficient production of microalgae, thus contributing to the mitigation or reduction of the impacts of climate change.

[0049] The above embodiments can be summarized as follows:

[0050] The above embodiment discloses a culture apparatus (10) for culturing microalgae in a culture medium (L), comprising: a translucent liquid storage section (12) capable of storing a storage liquid (W); a storage section (14) disposed inside the liquid storage section and capable of containing the culture medium and the microalgae; and a frame member (46) disposed inside the liquid storage section, wherein the side surface (14S) of the storage section is restricted by the frame member.

[0051] The housing portion is made of a flexible material, and a fixing member (48) made of a flexible material is welded to the side surface of the housing portion, and the fixing member is provided with an insertion hole (483) through which the frame member is inserted.

[0052] The fixing member has a welded surface (481) that extends along the side surface of the housing portion, and the welded surface is welded in a planar manner to the side surface of the housing portion.

[0053] The culture apparatus includes a liquid tank frame (16) that supports the liquid storage section, the liquid storage section is made of a flexible material, the frame member is fixed to the upper end of the liquid tank frame and extends downward from the upper end of the liquid storage section through the interior of the liquid storage section.

[0054] The culture apparatus is provided with a gas supply pipe (32) located at the bottom (143) of the containment section for supplying gas (G) into the containment section, wherein the specific gravity of the gas supply pipe is greater than the specific gravity of the culture medium.

[0055] A plurality of guide sections (36) are provided within the housing section, and the gas supply pipe has a plurality of gas supply ports (33) at positions corresponding to the plurality of guide sections for supplying the gas toward the plurality of guide sections, and each of the plurality of guide sections has a suction port (361) for drawing the culture solution from the outside to the inside of the guide section when the gas is supplied, and a discharge port (362) for discharging the culture solution from the inside to the outside of the guide section.

[0056] The above embodiment discloses a culture method for culturing microalgae in a culture medium (L), wherein a storage liquid (W) is stored inside a translucent storage section (12), the culture medium and the microalgae are contained inside a containment section (14) located inside the storage section, and the microalgae are cultivated in the containment section while restricting the side surface (14S) of the containment section with a frame member (46) located inside the storage section.

[0057] Furthermore, the present invention is not limited to the embodiments described above, and various configurations can be taken without departing from the spirit of the invention. [Explanation of Symbols]

[0058] 10...Culture device 12...Liquid storage part 14…Storage section 16…Liquid tank frame 46...Frame members 48...Fixing members

Claims

1. A culture apparatus for culturing microalgae in a culture medium, A translucent liquid storage section capable of storing liquid, A storage section is provided inside the liquid storage section, made of a flexible material, and capable of containing the culture solution and the microalgae, A plurality of frame members arranged inside the liquid storage section, The housing section is provided with a gas supply pipe located at the bottom, which pushes the bottom downwards due to its own weight and supplies gas into the housing section. Each of the multiple frame members has a frame body portion configured to be convex downwards, and the housing portion is arranged inside the convex downwards frame body portion. The multiple frame members are arranged at intervals from each other in the width direction of the housing section and are inserted into insertion holes formed in the multiple fixing members provided on the side surface of the housing section. A culture apparatus in which the side surface of the housing section is restricted by a plurality of frame members.

2. In the culture apparatus according to claim 1, The aforementioned fixing member is made of a flexible material and is welded to the side surface of the culture apparatus.

3. In the culture apparatus according to claim 2, The fixing member has a welded surface that extends along the side surface of the housing portion, A culture apparatus in which the welded surface is welded in a planar manner to the side surface of the housing portion.

4. In the culture apparatus according to any one of claims 1 to 3, The system includes a liquid tank frame that supports the liquid storage section, The liquid storage section is made of a flexible material, The aforementioned frame member is fixed to the upper end of the liquid tank frame and extends downward from the upper end of the liquid storage section within the liquid storage section of the culture apparatus.

5. In the culture apparatus according to any one of claims 1 to 4, Multiple guide sections are provided within the aforementioned housing section. The gas supply pipe has a plurality of gas supply ports that supply the gas toward the plurality of guide portions at positions corresponding to the plurality of guide portions, Each of the aforementioned multiple guide sections is When the aforementioned gas is supplied, the suction port draws the culture medium from the outside to the inside of the guide section, An outlet for discharging the culture medium from the inside to the outside of the guide section, A culture apparatus having the following features.

6. In the culture apparatus according to any one of claims 1 to 5, The culture apparatus comprises a gas supply pipe that extends along the width direction inside the housing.

7. A method for culturing microalgae in a culture medium using a culture apparatus according to any one of claims 1 to 6, The liquid is stored inside the liquid storage section. The culture solution and the microalgae are contained within the containment section, which is located inside the liquid storage section. A cultivation method comprising culturing the microalgae within the storage section while restricting the sides of the storage section with a plurality of frame members arranged inside the liquid storage section.

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