JP7133164B2 - Algae culture reactor - Google Patents

Description

The present invention relates to an algae culture reactor for culturing algae.

Biomass (also referred to as biofuel) is actively utilized as a fuel that does not depend on fossil resources, and algae can be exemplified as one of them. Algae culture methods are broadly classified into open and closed types. An open culture facility comprises a large pond or similar open vessel, an agitation device, and a carbon dioxide injection device. An open-type culture facility has a simple configuration, and can reduce capital investment. However, since it is an open type, it is easy for harmful bacteria and foreign substances to enter from the air, and sometimes the cultured algae are completely destroyed by the harmful bacteria, and the products are contaminated with foreign substances.

Also, in an open culture facility, light is applied from the surface of the water, but the light does not reach beyond a certain water depth. For this reason, algae at a deep position cannot photosynthesise and grow with difficulty, making it difficult to secure a large water depth. On the other hand, the solubility of carbon dioxide depends on the distance that bubbles rise in the water, ie, the water depth. Therefore, if the water depth is small, the solubility of carbon dioxide to be injected is also limited.

A closed culture facility can reliably prevent the contamination of harmful bacteria and dust. In addition, since it is possible to irradiate light not only from the surface of the water but also from the side of the container in a closed type culture facility, it is possible to utilize the space in the height direction by devising the structure. Also, by using the space in the height direction, it is possible to increase the water depth. Therefore, it becomes possible to increase the solubility of carbon dioxide. However, closed-type culture facilities generally have complicated structures and require high capital investment. Furthermore, contamination inside the container may reduce the light transmittance and reduce the culture efficiency. There is also the problem that cleaning the inside of the container is not easy because of the closed type.

As a closed type culture facility, for example, the photosynthetic microalgae culture apparatus of Patent Document 1 can be exemplified. The photosynthetic microalgae culture apparatus of Patent Document 1 includes a culture vessel for accommodating a mixture of photosynthetic microalgae and a culture solution to culture the photosynthetic microalgae. This culture vessel is made of a light-permeable material, and the three-dimensional shape formed by the inner surface of the vessel has a silhouette elongated in one direction (height direction). Carbon dioxide is supplied to the liquid mixture in the culture container from the lower end of the inner surface of the culture container by means of an aeration means. The photosynthetic microalgae culture apparatus of Patent Document 1 also has the same problem as the above-described closed type culture facility.

JP 2011-254766 A

As described above, it is not easy to clean the inside of the closed type culture tank. Therefore, the development of a structure capable of simplifying the cleaning work is required. As another problem, in order to culture algae efficiently, it is necessary to uniformly supply light and carbon dioxide to the culture solution in the culture tank. However, with the configuration of Patent Document 1, since carbon dioxide is supplied from the bottom end of the culture vessel, the supplied carbon dioxide dissolves in the culture solution, but the culture solution in the culture tank must be stirred sufficiently. , the dissolved carbon dioxide may not be homogenized. Further, with the configuration of Patent Document 1, the culture solution near the inner surface of the culture container is sufficiently exposed to light, but the culture solution near the center of the culture container may not be sufficiently exposed to light.

In view of such problems, the present invention is an algae culture reactor that can simplify the cleaning work of the culture tank and can homogenize the light and carbon dioxide by sufficiently stirring the culture solution inside the culture tank. is intended to provide

In order to solve the above problems, a representative configuration of the algae culture reactor according to the present invention is an algae culture reactor for culturing algae, comprising a double-tube structure culture tank consisting of an outer tube and an inner tube, The outer tube is made of glass, the inner tube is made of resin, and the inner tube contains a culture solution containing algae and is detachable from the outer tube.

In the above configuration, the culture tank has a double-tube structure, and the culture solution is accommodated in the inner tube. Since the inner tube is made of resin, the cost is low. Therefore, if the inner surface of the inner tube becomes dirty due to algae adhering to it, or if you change the type of algae you want to culture, you can remove the dirt from the culture tank without cleaning by replacing the inner tube. can do. At this time, since the culture solution is contained in the inner tube, dirt does not adhere to the inner surface of the outer tube. Therefore, cleaning of the culture vessel is completed by cleaning only the outer surface of the outer tube. Therefore, according to the above configuration, the cleaning work of the culture tank can be simplified, and the burden on workers can be greatly reduced.

In order to solve the above-mentioned problems, another configuration of the algae culture reactor according to the present invention is an algae culture reactor for culturing algae, comprising a culture tank, a culture fluid inlet disposed near the lower end of the culture tank, and gas. An inlet, an air-lift pump tube that is arranged inside the culture tank and communicates with the culture medium inlet and the gas inlet and extends from the bottom end to the vicinity of the top end of the culture tank, and near the bottom end of the culture tank and outside the air-lift pump tube. It is characterized by having a culture solution outlet.

In such a configuration, the culture solution is mixed with gas in the air lift pump pipe (supply pipe) and supplied into the culture vessel. Then, the culture solution moves from the inside to the outside of the supply pipe in the culture tank. Then, the culture solution can be circulated by connecting the culture solution outlet and the culture solution inlet near the lower end of the culture tank. This circulation can be circulated even if there is only one culture tank, or it can be circulated even if a plurality of culture tanks are connected to each other. Therefore, the culture medium inside the culture tank is sufficiently agitated, which is effective in homogenizing light and dissolved carbon dioxide.

It is preferable that a plurality of the culture tanks are arranged side by side, and the culture fluid inlet and the culture fluid outlet of the adjacent culture tanks are connected. This makes it possible to sequentially circulate the culture solution through the plurality of culture tanks. Therefore, it becomes possible to heighten the effect mentioned above.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide an algae culture reactor capable of simplifying the cleaning work of the culture tank and homogenizing the light and carbon dioxide by sufficiently stirring the culture solution inside the culture tank. can.

It is a figure explaining the alga culture reactor concerning this embodiment. It is a figure explaining the culture tank of FIG. It is a figure explaining the transmittance|permeability spectrum dependence measurement result of several materials. 4 is a photograph of culture tanks of Examples and Comparative Examples. FIG. 4 is a diagram for explaining movement of a culture solution in a culture tank; It is a figure explaining circulation of the culture solution in the reactor of Fig.1 (a).

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present invention are omitted from the drawings. do.

FIG. 1 is a diagram illustrating an algae culture reactor (hereinafter referred to as reactor 100) according to this embodiment. 1(a) is a front view of the reactor 100, and FIG. 1(b) is a plan view of the reactor 100. FIG. The reactor 100 of this embodiment is an apparatus for culturing algae. As shown in FIGS. 1(a) and 1(b), the reactor 100 of this embodiment comprises a plurality of culture tanks 110. FIG. In addition, although the configuration in which ten culture tanks 110 are arranged side by side is illustrated in this embodiment, the configuration is not limited to this, and the number of culture tanks can be changed as appropriate.

FIG. 2 is a diagram for explaining the culture tank 110 of FIG. 2(a) is a diagram illustrating the outer tube 120, and FIG. 2(b) is a diagram illustrating the inner tube 140. FIG. The culture tank 110 of this embodiment has a double-tube structure including an outer tube 120 shown in FIG. 2(a) and an inner tube 140 shown in FIG. 2(b).

The outer tube 120 shown in FIG. 2(a) is a glass tube. The upper portion of outer tube 120 is supported by upper frame 102 of reactor 100 . A support jig 122 is attached to the lower end of the outer tube 120 . A jig 122 is connected to the lower frame 104 of the reactor 100 . Thereby, the lower portion of the outer tube 120 is supported by the lower frame 104 via the jig 122 .

As shown in FIGS. 1 and 2(a), a supply means 105 is arranged below the lower frame 104. As shown in FIG. The supply means 105 is provided with a culture solution inlet 130a and a gas inlet 130b. A culture fluid pipe 106 is connected to the culture fluid inlet 130a, and a gas pipe 108 is connected to the gas inlet 130b. By attaching the lower end of an inner tube 140 (to be described later) to the supply means 105 , a culture solution inlet 130 a and a gas inlet 130 b are arranged at the lower end of the culture tank 110 .

The inner tube 140 shown in FIG. 2(b) is a bag made of resin that is arranged inside the outer tube 120 in the culture tank 110 and stores the algae-containing culture solution. The inner tube 140 is detachable from the outer tube 120 . At the lower end of the inner tube 140, a culture solution outlet 144 for discharging the culture solution is provided outside the supply pipe 150, which will be described later.

As described above, the inner tube 140 is removable from the outer tube 120 . By using the inner tube 140 as a bag made of resin, the inner tube 140 can be made inexpensive. Therefore, when dirt adheres to the inner surface of the inner tube 140, it becomes possible to remove the inner tube 140 from the outer tube 120 and use the inner tube 140 once and for all (disposable). As the resin used for the inner pipe 140, it is preferable to use a soft resin. As a result, it is possible to easily deform the inner tube 140 so as to be in close contact with the outer tube 120 by filling with the culture solution.

A supply pipe 150 that is a pipe for an air lift pump is arranged inside the inner pipe 140 . The supply pipe 150 extends from the lower end of the inner pipe 140 to near the upper end. The lower end of the supply pipe 150 is connected to the introduction side connection portion 142 and the upper end is open inside the inner pipe 140 . By connecting the introduction-side connecting portion 142 to the supply connector 112 of the supply means 105, the supply pipe 150 and the inner pipe 140 communicate with the culture solution inlet 130a and the gas inlet 130b. Thereby, the culture solution and carbon dioxide are supplied to the inner tube 140 through the supply tube 150 . Also, by connecting the culture solution outlet 144 to the connecting connector 114 , the culture solution can be discharged to the outside of the inner tube 140 .

When assembling the culture tank 110 , the inner tube 140 is first inserted into the outer tube 120 . Then, the introduction-side connecting portion 142 of the inner tube 140 is connected to the supply connector 112 , and the culture fluid outlet 144 is connected to the connecting connector 114 . Then, the lid 160 is fitted over the outer tube 120 and the outer tube 120 is attached to the upper frame 102 and the lower frame 104 . Thus, the culture tank 110 is assembled. At this time, since the outer tube 120 functions as a protective tube outside the inner tube 140, it is possible to suitably prevent damage such as breakage of the inner tube 140 made of resin.

FIG. 3 is a diagram for explaining the measurement results of the transmittance spectrum dependence of a plurality of materials. In FIGS. 3A to 3D, the wavelength of light is plotted on the horizontal axis, and the transmittance of light is plotted on the vertical axis. The transmittance spectrum dependence was measured by measuring the wavelength dependence of the sample light transmittance using air as a blank.

FIG. 3(a) shows transmittance spectrum dependence of a blank in which no measurement object is placed. As shown in FIG. 3(a), in the blank state, the intensity is almost 100% at any wavelength from 200 nm to 800 nm. That is, in a blank state, naturally no attenuation of light occurs (almost 100% of light is transmitted).

FIG. 3(b) shows transmittance spectrum dependency when a glass plate is placed as a measurement target. As shown in FIG. 3(b), when the glass plate is placed, the intensity becomes almost 0% in the wavelength band from 200 nm to 300 nm, that is, in a part of the ultraviolet wavelength band. On the other hand, above 300 nm, the intensity is about 90%. From this, it can be understood that the glass plate can effectively transmit light in the visible light region while cutting ultraviolet rays efficiently.

FIG. 3(c) shows the transmittance spectrum dependency when the sheet of resin used for the inner tube is arranged as a measurement object. As shown in FIG. 3(c), when the sheet of resin used for the inner tube is arranged, the intensity in the wavelength band of 200 nm to 300 nm, ie, a part of the ultraviolet wavelength band, is about 50%. At 300 nm or more, the intensity gradually increases as the wavelength becomes longer, reaching about 90% at 800 nm. From this, it can be understood that the resin sheet used for the inner tube cuts ultraviolet rays by about half and allows good transmission of light in the visible light range, though not as well as the glass plate.

FIG. 3(d) shows transmittance spectrum dependence when an acrylic plate is placed as a measurement target. As shown in FIG. 3(d), when the acrylic plate is placed, the intensity of the light in the wavelength band of 200 nm to 350 nm, which includes the ultraviolet wavelength band, becomes about 10%. And when the wavelength of light exceeds 350 nm, the intensity rises to about 50%. However, as the wavelength of light becomes longer, the intensity gradually decreases, reaching approximately 25% at 800 nm. From this, it can be understood that although the acrylic plate can cut most of the ultraviolet light, it also cuts a large amount of light in the visible light region.

Visible light is absorbed by algae during photosynthesis. For this reason, when the visible light region is largely cut, photosynthesis of algae is inhibited. Therefore, the acrylic plate is not suitable as the material for the outer tube 120 and the inner tube 140 . On the other hand, it is generally well known that ultraviolet rays damage the chromosomes of organisms. For this reason, it is beneficial in culturing algae to cut ultraviolet rays to a large extent. Therefore, the glass and the resin sheet used for the inner tube are suitable materials for the outer tube 120 and the inner tube 140 .

If both the outer tube and the inner tube are made of glass, the culture medium will grow inside the glass inner tube. If the inner tube is made of glass, the part cost is high, so it cannot be used once and for all. Therefore, if dirt adheres to the inner surface of the inner tube, the inside must be washed, which makes no sense to use a double tube structure.

Further, if both the outer tube and the inner tube are made of resin, there is a risk that both the outer tube and the inner tube will be damaged when a sharp object comes into contact with them. Then, the culture solution inside leaks out. From this, it can be seen that glass, which has high strength, is suitable for the material of the outer tube instead of resin.

FIG. 4 is a photograph of the culture tanks of Examples and Comparative Examples. FIG. 4(a) is a photograph of the culture tank 110 of the embodiment in which the resin inner tube 140 is arranged inside the glass outer tube 120, and the one on the left is inside the inner tube 140. It is in a state in which the culture medium is contained, and the two tubes on the center and right side are in a state in which the culture medium inside the inner tube 140 is removed. FIG. 4(b) is a photograph of a culture tank of a comparative example consisting only of an inner tube, in which the culture solution inside the inner tube 140 has been removed.

As shown in FIG. 4( a ), in the culture tank 110 of the embodiment, no algae adhere to the inner surface of the inner tube 140 when the culture solution is removed, and the scenery behind the outer tube 120 can be confirmed. On the other hand, as shown in FIG. 4(b), in the culture tank of the comparative example, algae adhered to the inner surface of the inner tube when the culture solution was removed, so the inner tube became opaque.

When the inner tube becomes opaque due to algae adhering to the inner surface as in the comparative example, the light transmittance decreases. As a result, the photosynthetic efficiency of the algae is reduced, resulting in poor cultivation. On the other hand, in the examples, since no algae adhere to the inner surface, the inner tube is transparent and allows sufficient light transmission. Therefore, by adopting a double tube structure of the outer tube 120 and the inner tube 140 as in the culture tank 110 of the embodiment, it is possible to increase the photosynthetic efficiency of algae and obtain high culture efficiency. In addition, the reason why algae do not adhere to the inner surface of the inner tube 140 in the example is considered to be that the ultraviolet rays are largely cut off by the outer tube 120, thereby greatly reducing the amount of algae dying.

As described above, according to the reactor 100 of the present embodiment, the culture tank 110 has a double-tube structure, and the inner tube 140 containing the culture solution is made of resin, so the cost is low. Therefore, if the inner surface of the inner tube 140 becomes dirty due to adhesion of algae or the like, the dirt in the culture tank 110 can be easily removed by replacing the inner tube 140 . Since the culture medium is housed in the inner tube 140, the inner surface of the outer tube 120 will not be stained. Therefore, cleaning of the inner tube 140 is not necessary, and cleaning of the culture tank 110 is completed by cleaning only the outer surface of the outer tube 120 . As a result, the cleaning work of the culture tank 110 can be simplified, and the burden on workers can be greatly reduced.

5A and 5B are diagrams for explaining the movement of the culture medium in the culture tank 110. FIG. To facilitate understanding, in FIG. 5, the culture solution is indicated by hatching, the flow of the culture solution is indicated by black arrows, and the flow of gas (carbon dioxide) is indicated by white arrows. As shown in FIG. 5, when the culture medium and gas are supplied from the lower end of the culture tank 110, they enter the supply pipe 150. As shown in FIG. At this time, the culture solution and the gas enter the supply pipe 150 together, so that the air bubbles float upward, and the culture solution is transported upward by the air bubbles. This configuration is commonly referred to as an airlift pump.

The culture solution reaches the upper end of the supply pipe 150 and overflows to the outside of the supply pipe 150 by being transported by the air bubbles. Then, the liquid level of the culture solution inside the inner tube 140 rises, the culture solution flows downward inside the inner tube 140, and is discharged to the outside of the inner tube 140 and the culture tank 110 through the culture solution outlet 144. . By causing the culture solution to flow within the culture tank 110 in this way, it is possible to uniformly supply light and carbon dioxide compared to the case where the culture solution stays at the same place within the culture tank 110 .

FIG. 6 is a diagram illustrating the circulation of the culture medium in the reactor 100 of FIG. 1(a). As described above, in the reactor 100, a plurality of (10 in this embodiment) culture tanks are arranged side by side. As a feature of the reactor 100 of this embodiment, the plurality of culture tanks 110 are connected to the culture medium inlet 130a and the culture medium outlet 144 of the adjacent culture tanks 110, respectively. For convenience of explanation, the ten culture tanks 110 shown in FIG.

Specifically, the culture fluid outlet 144 (see FIG. 2(b)) of the first culture tank 110 on the leftmost side in FIG. connected to As a result, the culture solution discharged from the first culture tank 110 flows into the second culture tank 110 . Then, the liquid level of the culture solution in the inner tube 140 rises in the second culture tank 110 . As a result, the inner tube 140 flows and moves downward in the second culture tank 110 .

The culture fluid outlet 144 of the second culture tank 110 is connected to the culture fluid inlet 130a of the third culture tank 110 . Therefore, the culture solution discharged from the second culture tank 110 flows into the third culture tank 110 . By connecting the culture fluid outlets 144 and the culture fluid inlets 130a of the plurality of culture tanks 110 in this manner, the culture fluid can be circulated through the plurality of culture tanks 110 in order.

The culture solution circulated through the first to ninth culture tanks 110 as described above is discharged from the ninth culture tank 110 and flows into the tenth culture tank 110 . In this embodiment, the culture fluid outlet 144 of the tenth culture tank 110 and the culture fluid inlet 130a of the first culture tank 110 are connected. As a result, the culture solution discharged from the tenth culture tank 110 flows into the first culture tank 110 . Therefore, it is possible to continue to circulate the culture solution through the plurality of culture tanks 110 .

As described above, according to the reactor 100 of this embodiment, the culture solution can be circulated through the plurality of culture tanks 110 . At this time, circulation is possible without damaging the algae cells by using an air lift pump instead of mechanical means. By circulating the culture solution as described above, gas, that is, carbon dioxide, which is a nutrient for the algae, is uniformly supplied to the entire culture solution. In addition, by circulating the culture solution, the culture solution can be uniformly exposed to light, and adhesion of algae to the inner surface of the inner tube 140 can be suppressed appropriately.

In addition, in this embodiment, although the culture tank 110 having a double-tube structure is exemplified, it is not limited to this. Even if the culture vessel has a single-tube structure, it is possible to obtain the above-described effect of circulating the culture solution by connecting a plurality of culture vessels. When only one culture tank 110 is provided, the culture tank 110 and the tank can be connected by connecting the culture fluid inlet 130a and the culture fluid outlet 144 of the culture tank 110 to a storage tank (not shown) for the culture fluid. The culture medium can be circulated between them. In addition, by connecting the culture fluid inlet 130 a and the culture fluid outlet 144 of one culture tank 110 , it is possible to keep the culture fluid circulating in one culture tank 110 .

In this embodiment, the outer tube 120 is exemplified as a glass tube, but the present invention is not limited to this. For example, when using a resin that can effectively transmit light in the visible light region while efficiently cutting ultraviolet rays, the outer tube 120 can be made of resin. However, even in this case, from the viewpoint of protecting the inner tube 140, it is preferable that the resin used for the outer tube 120 has appropriate rigidity.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood.

INDUSTRIAL APPLICABILITY The present invention can be used as an algae culture reactor for culturing algae.

DESCRIPTION OF SYMBOLS 100... Reactor, 102... Upper frame, 104... Lower frame, 105... Supply means, 106... Culture fluid pipe, 108... Gas pipe, 110... Culture tank, 112... Supply connector, 114... Connection connector, 120... Outer pipe, DESCRIPTION OF SYMBOLS 122... Jig, 130a... Culture fluid inlet, 130b... Gas inlet, 140... Inner tube, 142... Introduction side connection part, 144... Culture fluid outlet, 150... Supply pipe, 160... Lid

Claims (2)

An algae culture reactor for culturing algae, comprising:
a culture tank with a double-tube structure consisting of an outer tube and an inner tube;
a culture solution inlet and a gas inlet arranged near the lower end of the culture tank;
a pipe for an air lift pump disposed inside the inner pipe of the culture tank and communicating with the culture solution inlet and the gas inlet and extending from the lower end to the vicinity of the upper end of the inner pipe ;
The outer tube is made of glass,
The inner tube is made of resin,
The inner tube contains a culture solution containing algae and is detachable from the outer tube,
An algae culture reactor comprising a culture solution outlet near the lower end of the inner tube and outside the air lift pump tube . 2. The algae culture reactor according to claim 1 , wherein a plurality of said culture tanks are arranged side by side, and said culture medium inlet and said culture medium outlet of said adjacent culture tanks are connected.

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