JPH0564577A - Method and device for culturing photosynthetic microorganism - Google Patents

Abstract

PURPOSE:To enable the massive culture of an adhesive photosynthetic microorganism by a new method using optical fibers and fibrous optical conductors emitting light from their side surfaces, and to realize the saving of energy by the effective utilization of light energy. CONSTITUTION:Solar light and/or artificial light is transmitted to a culture device through an optical fiber 3. Fibrous optical conductors 4 emitting light from their side surfaces are connected to the optical fiber 3, and inserted into a solution in a container to introduce the transmitted solar light and/or artificial light into the culture tank 1. An adhesive photosynthetic microorganism such as adhesive photosynthetic bacterium or adhesive fine alga is adhered to the optical conductors and cultured. The optical conductors include optical fibers having grooves carved on their surfaces and glass fibers containing a light- diffusing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosynthetic microorganism culturing method and apparatus, and more particularly to a culturing method and apparatus using adherent photosynthetic microorganisms such as adherent photosynthetic bacteria and / or adherent microalgae. The culturing method and apparatus of the present invention include treatment of organic wastewater, production of hydrogen as clean energy, method and apparatus for producing various useful substances, and carbon dioxide in the atmosphere that contributes to global warming. Can be used for immobilization, etc. The present invention relates to a culture device for adhering photosynthetic microorganisms such as a novel adhering photosynthetic bacterium and / or adhering microalgae different from the prior art,
At the same time, it provides innovative culture technology that also contributes to global environmental conservation.

[0002]

2. Description of the Related Art Conventionally, in the culturing technology using photosynthetic microorganisms, mainly buoyant photosynthetic microorganisms are cultivated. Most of the equipment is a fluidized bed type and the light is emitted from the outer wall of the equipment by a rod-shaped fluorescent lamp in the tank. The mainstream method is to supply the liquid, or to attach a rod-shaped fluorescent lamp or the like to the center of the inside of the apparatus to supply light to the liquid in the tank. However, recently, various technologies have been researched and developed, and as a typical technology, sunlight and / or artificial light is transmitted through an optical fiber, and the transmitted light is further diffused into a liquid in a tank by a special surface emitting fiber. Alternatively, a method and a device for culturing a photosynthetic microorganism by providing a scattering groove in a longitudinal direction on a resin rod-shaped rod and diffusing light linearly and linearly in a tank have been developed. On the other hand, as for the adhering photosynthetic microorganisms, a multi-stage or rotating disc type culturing device has been proposed in which the photosynthetic microorganisms are adhered to a plate-shaped adherent carrier and sunlight and / or artificial light is irradiated from the outside.

[0003]

However, the conventional photoculturing apparatus for photosynthetic microorganisms has the following technical problems, and various researches are carried out at each research institute in order to improve these defects. It is being appreciated. (1) In the culture method and apparatus for supplying light energy with a fluorescent lamp, the amount of light energy that can be transferred is small (transfer efficiency is about 10%) regardless of whether the supply method is an outside tank type or an inside tank type, and a photosynthetic microorganism. It is not suitable for large-scale culture and concentrated culture of (2) When culturing floating photosynthetic microorganisms, the photosynthetic microorganisms are concentrated on the inner wall of the culture device in (1) the outer tank type and on the surface of the fluorescent lamp in the inner tank type. And the diffusion of light into the liquid in the tank is inhibited, and the attached photosynthetic microorganisms are exposed to strong light and die, or the activity is significantly deteriorated. (3) In the culture of buoyant photosynthetic microorganisms, the method of transmitting light energy through an optical fiber in the tank has a much larger amount of transmitted light energy than the fluorescent lamp method, but the number of photosynthetic microorganisms is very small and numerous in a large number of optical fibers. It adheres densely, loses the light diffusion function over time, and also causes the optical fibers to clog each other, obstructing the circulation of the liquid in the tank. For this reason, it is necessary to frequently clean the optical fiber, and operation management is extremely complicated.

(4) The light receiving area is limited in a multi-stage type or rotating disk type culturing device in which adherent photosynthetic microorganisms are adhered on a plate-shaped adherent carrier and sunlight and / or artificial light is irradiated from the outside of the tank. Therefore, the light energy cannot be effectively used, and it is not suitable for large-scale culture of photosynthetic microorganisms. (5) When a large amount of adhering photosynthetic microorganisms are attached to a large number of ultra-fine optical fibers, the amount of transmitted light energy is much larger than that of the fluorescent lamp system, but the optical fibers are blocked by each other and the circulation of the liquid in the tank is obstructed. It Therefore, cleaning of the optical fiber is required frequently, and operation management is extremely complicated. (6) The method of adhering the adhering photosynthetic microorganisms to the special surface-emitting fiber has a much larger amount of transmitted light energy than the fluorescent lamp method, but since the surface area of the adhering carrier is small,
Not suitable for large-scale culture of photosynthetic microorganisms. The present invention provides a novel method and apparatus for cultivating a photosynthetic microorganism, which ameliorates these deficiencies of the conventional apparatus and enables markedly large-scale cultivation as compared with the conventional technology, which is energy-saving and is significantly easy to operate. This is an issue.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method for culturing adherent photosynthetic microorganisms such as adherent photosynthetic bacteria and adherent microalgae in which sunlight transmitted by an optical fiber and / Or artificial light is introduced into the culture tank by a fibrous light guide that emits light from the side surface inserted into the liquid in the tank, and a photosynthetic microorganism adherent to the surface of the fibrous light guide is introduced. This is a method for culturing a photosynthetic microorganism, which is characterized in that it is adhered and cultured. Further, in the present invention, in a device for culturing adherent photosynthetic microorganisms such as adherent photosynthetic bacteria and adherent microalgae, a culture tank, an optical fiber for transmitting sunlight and / or artificial light, and a tank connected to the optical fiber It has a fibrous light guide that emits light from the side surface that is inserted into the internal liquid,
In addition, the photosynthetic microorganism culturing apparatus is characterized in that an adhesive photosynthetic microorganism adheres to the fibrous light guide and is cultured.

In the above culture device, the fibrous light guide can be integrally formed by coating the surface of the carbon dioxide and oxygen permeable membrane. In this case, the fibrous light guide is woven in a net shape. The carbon dioxide and oxygen permeable membrane is preferably hollow fiber. The surface of the hollow fiber-shaped permeable membrane can be covered with a fibrous light guide to be integrated into a fibrous structure. In addition, it is preferable that the fungus body or alga body adhered to the surface of the light guide body and grown is given a shear flow or the like to be regularly peeled off.

That is, the present invention is intended for culturing adherent photosynthetic microorganisms such as adherent photosynthetic bacteria and / or adherent microalgae, and uses sunlight and / or artificial light (fluorescent lamp, halogen lamp, metal halide lamp and xenon). Lamp) is transmitted to the culture device by an optical fiber, and the transmitted sunlight and / or artificial light is introduced into a fibrous light guide that emits light from the side inserted into the bath liquid, and the light is emitted from this side. A method and an apparatus for culturing a photosynthetic microorganism, which comprises adhering an adherent photosynthetic microorganism on the surface of a fibrous light guide to be emitted and culturing. As the fibrous light guide that emits light from the side surface, any fiber can be used as long as it has a property of transmitting light and a property of emitting light from the side surface, for example, an optical fiber or acrylic with a groove engraved on the side surface. It may be a fiber, or glass or acrylic fiber containing a diffuser.

The present invention is particularly suitable for culturing adherent microalgae among adhering photosynthetic microorganisms, does not require any special means for immobilizing microorganisms, and reduces ancillary facilities such as solid-liquid separation means. It can be omitted. Further, according to the present invention, since these gases necessary for growth are supplied through a membrane permeable to carbon dioxide (CO ₂ ) and oxygen, the problem of foaming caused by aeration can be avoided. Furthermore, the present invention is also an epoch-making method and apparatus for culturing photosynthetic microorganisms that can simultaneously solve the problem of adhesion, which is the most problematic in culturing photosynthetic microorganisms, and can also intentionally renew the microbial membrane.

[0009]

[Function] The photosynthetic microorganism culturing apparatus of the present invention is provided with sunlight and / or
Alternatively, artificial light is introduced into a fibrous light guide that emits light from the side inserted into the culture tank using an optical fiber as a transmission medium, and the light energy is efficiently applied to the adherent photosynthetic microorganisms that grow by adhering to the surface. It is a culture method and device whose main feature is to supply well. Adherent photosynthetic bacteria and /
Or, adhering photosynthetic microorganisms such as adhering microalgae have a property of growing like a mat on a solid surface, can normally obtain light necessary for growth, and further have sufficient carbon dioxide (CO ₂ ) and / or oxygen. Solid-liquid interface and / or
Alternatively, it grows by adhering to a gas-solid interface that allows sufficient water supply.

Most conventional photosynthetic microorganism culture devices are those in which fluorescent lamps or optical fibers are installed in a tank and dispersed in the liquid in the tank. In this type of device, adhesion of bacterial cells or algae is studied. It is a major obstacle in terms of aspects and / or practical use. On the other hand, in the present invention, since the adherent photosynthetic microorganisms are adhered to the surface of the light guide that emits light from the side that is the light source for the liquid in the tank, the photosynthesis in the liquid in the tank is performed. Microorganisms do not exist, or even if they exist, they cannot be supplied with light and can hardly proliferate.Therefore, there is only a very low concentration. It is an innovative photosynthetic microorganism culture device that solves this problem by minimizing body adhesion. Further, since the conventional floating photosynthetic microorganism culturing device diffuses light into the liquid in the tank, when the culturing cells or algae are at a high concentration, the light reaching distance is limited and the utilization efficiency of light energy is reduced. On the other hand, according to the present invention, since the adherent photosynthetic microorganisms are adhered to the surface of the light guide that emits light from the side surface that is the source of light to the liquid in the tank, the light is inserted into the liquid in the tank. This is an innovative photosynthetic microorganism culture device that can increase the surface area of the photoconductor and increase the bacterial cell concentration in the tank. Moreover, when this fibrous light guide is woven in a net shape, it has a very large surface area and exhibits an excellent function as a carrier for adherent microorganisms.

The fungus body or alga body adhered and grown on the surface of the light guide is easily and regularly peeled off, so that the fungus body or alga body is always kept in a vigorously growing state. Further, according to the present invention, in the conventional photosynthetic microorganism culture, carbon dioxide (CO ₂ ) and / or oxygen necessary for growth are diffused as fine bubbles from a diffusing device such as a diffusing tube into a liquid in a tank to be dissolved. Although occupying the mainstream, in this type of device, the foaming of the culture solution is a major obstacle in terms of research and / or practical use. On the other hand, in the present invention, carbon dioxide (CO ₂ ) and / or oxygen necessary for the growth of the photosynthetic microorganism are diffused and dissolved from the membrane 5 permeable to carbon dioxide (CO ₂ ) and oxygen at a close distance. Since it can be utilized, it grows extremely efficiently, and since it is not released as bubbles into the liquid in the tank, it is an innovative photosynthetic culture method and device that solves the problem of foaming.

[0012]

The present invention will be specifically described below with reference to the drawings, but the present invention is not limited to these embodiments. Example 1 FIG. 1 shows a schematic explanatory view of a culture device of the present invention. Figure 1
The present invention relates to a photosynthetic microorganism culturing device in which a surface of a membrane permeable to carbon dioxide (CO ₂ ) and oxygen is covered with a fibrous light guide and is integrally inserted into a liquid in a tank. In FIG.
The light transmitted from the sunlight and / or the artificial light 2 through the optical fiber 3 is introduced into the fibrous light guide 4 which emits light from the side surface. The light guide 4 is made of a fibrous material woven in a net shape, has a very large surface area, and exhibits an excellent function as a carrier for adherent microorganisms. On the other hand, air, carbon dioxide (CO ₂ ) -enriched air and / or carbon dioxide (CO
₂ ) 8 is a membrane 5 permeable to carbon dioxide (CO ₂ ) and oxygen
Is supplied to. The photosynthetic microorganisms adhere to the surface of the fibrous light guide 4 and can receive sufficient light, and carbon dioxide (CO ₂ ) and / or oxygen required for growth are carbon dioxide in a short distance. Since it can be received from the (CO ₂ ) and oxygen permeable membrane 5, it grows extremely efficiently. The in-tank solution is gently agitated by an agitator 6 usually located at the bottom of the culture tank 1 and comes into contact with adherent bacterial cells or algal cells. The tank liquid is regularly stirred by a stirring device 6 at the bottom of the culture tank 1.
The cells or algae that are rapidly stirred and adhered to and grow on the surface of the light guide are intentionally separated by applying a shear flow.

The peeling method is not limited to these, and strong light, heat generation and other methods may be used. The separated bacterial cells or algal cells are settled and then withdrawn from the bottom of the tank to be collected as surplus bacterial cells or algal cells. FIG. 2 is a cross-sectional view of a carrier fiber in which a hollow fiber-shaped carbon dioxide (CO ₂ ) and oxygen-permeable membrane 5 is coated with a fibrous light guide 4 on the surface thereof to form a fibrous structure. is there. This carrier fiber can be woven in a mesh form and can replace the 4,5 of FIG.

Example 2 Eight units (10 cm × 10 cm) of the light guide fiber net and hollow fiber gas permeable membrane of the present invention were used to obtain an effective volume of 1.8.
Insert into a 1-liter fermentor and use MKM medium to pH
Phormidium was cultured at 8.0 at a temperature of 20 ° C. The composition of the MKM medium is shown below. KNO 3750 mg MgSO ₄ .7H ₂ O 20 mg KH ₂ PO ₄ 25 mg Iron citrate 2.5 mg Seawater 500 ml Distilled water 500 ml Using the device of FIG. 1, the light from the 300 W artificial light source 2 is applied to the end of the light guide fiber 4. The gas permeable membrane 5 was supplied with air containing 5% of carbon dioxide at a pressure of 2 kgf / cm ² . The inside of the tank was usually gently stirred, and vigorous stirring was performed every 24 hours to peel off the algal cells, and then allowed to stand for 1 hour, the precipitated algal cells were extracted, and the same volume of fresh medium 7 was added.

Comparative Example 1 As a comparison, as shown in FIG. 3, a light was introduced into the light guiding fibers by directly illuminating the culture tank with a 300 W artificial light source 2 outside the culture tank. The illuminance on the side of the culture tank was set to 5000 lux, and other conditions were the same as in Example 2. The results are shown in Table 1.

[Table 1]

[0016]

According to the present invention, as described in detail, the following operational effects are exhibited. (1) The sunlight and / or artificial light transmitted by an optical fiber is introduced into a fibrous light guide that emits light from the side surface inserted into the culture tank, and adherent photosynthetic microorganisms are attached to the surface. Since the culture is performed by allowing it to cultivate, the photosynthetic microorganisms do not exist in the liquid in the tank, or even if they do exist, they cannot grow because they cannot receive the light supply. It is possible to minimize the adherence of bacterial cells or algae to the stirring device and various sensors. (2) It is extremely energy-saving compared to the method of diffusing light by a fluorescent lamp and can not only supply a large amount of light energy to the culture tank, but also can convert the sunlight and / or artificial light transmitted by an optical fiber into a surface or a rod. Light energy can be used extremely efficiently as compared with the method of diffusing from the light emitting body to the liquid in the tank.

(3) When the fibrous light guide is woven in a net shape, it has a very large surface area and exhibits a remarkably excellent function as a carrier for adherent microorganisms. (4) The fungus body or alga body that adheres to the surface of the light guide and grows is easily and regularly peeled off, so that the fungus body or alga body is always kept actively growing. , Efficient culture can be performed. (5) Carbon dioxide (CO ₂ ) and / or oxygen required for growth are carbon dioxide (C ₂ ) in the close range of photosynthetic microorganisms.
Since it diffuses and dissolves from the O ₂ ) and oxygen permeable membrane, it is not released as bubbles in the liquid in the tank, and no problems due to foaming occur.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a culture device of the present invention.

FIG. 2 is a cross-sectional view of a light guide 4.

FIG. 3 is a schematic explanatory view of a culture device used in a comparative example.

[Explanation of symbols]

1: Culture tank, 2: Light source, 3: Optical fiber, 4: Side-emission light guide fiber, 5: Carbon dioxide and oxygen permeable membrane, 6: Stirrer, 7: Medium, 8: Air and / or carbon dioxide enrichment Air, 9: drainage, 10: exhaust gas, 11: surplus bacterial cells or algae

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akiko Miya, 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute

Claims (3)

[Claims] 1. A method for culturing an adherent photosynthetic microorganism such as an adherent photosynthetic bacterium or an adherent microalga, wherein the sunlight and / or artificial light transmitted by an optical fiber is
Introducing into the culture tank by means of a fibrous light guide that emits light from the side surface inserted into the liquid in the tank, and culturing by adhering an adherent photosynthetic microorganism to the surface of the fibrous light guide. A method for culturing a photosynthetic microorganism, which comprises: 2. In a device for culturing adherent photosynthetic microorganisms such as adherent photosynthetic bacteria and adherent microalgae, a culture tank, an optical fiber for transmitting sunlight and / or artificial light, and an inside of the tank connected to the optical fiber. Photosynthesis, characterized in that it has a fibrous light guide that emits light from the side surface inserted into the liquid, and that adherent photosynthetic microorganisms adhere to the fibrous light guide and are cultured. Microbial culture device. 3. The photosynthetic microorganism culturing device according to claim 2, wherein the fibrous light guide is integrally formed by coating the surface of a carbon dioxide and oxygen permeable membrane.