JP2008283937A - Photobioreactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform optimum culture, even if the concentration of the culture solution becomes high, by effectively irradiating photosynthetic organisms, such as algae, with the light of a high-efficiency lamp. <P>SOLUTION: The photobioreactor is provided with a culture vessel 4 for holding a culture solution, a rotary shaft 12 rotatably placed in the culture vessel 4 and a field-emission lamp 16 fixed to the rotary shaft 12. The rotary shaft 12 is rotated, in a controlled manner of making the lamp 16 rotate about the rotary shaft, while making the lamp act as a stirring member for the culture solution, the light intensity and lighting of the lamp 16 are controlled to irradiate the culture solution with light of desired intensity, and the on/off timing of the lamp 16 is controlled to control the light reaction and the dark reaction of the photosynthetic organism, such as algae. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a light used for artificially cultivating microorganisms that require light for breeding, such as green algae such as Chlorella, Chlamydomonas and Botriococcus, and cyanobacterium such as Spirulina and Anavena in a culture tank. The present invention relates to a bioreactor (culture apparatus).

  In some patent documents including Japanese Patent Application Laid-Open No. 2006-014627, the algae are those that reproduce while generating and releasing oxygen by performing photosynthesis from light and carbon dioxide gas. It is described that it is several hundred times higher and algae such as chlorella have a wide range of uses for feed, food, fuel, etc., and are cultivated in large quantities using a large reproductive potential.

  Japanese Patent Laid-Open No. 2002-272447 describes a photobioreactor. In this photobioreactor, a photobioreactor is described in which a lamp is installed outside the culture tank and the algae in the culture tank are irradiated with light and cultured. Artificial photoculture, unlike solar culture that depends on the weather, enables stable photosynthesis at all times regardless of the season and weather.

  Japanese Patent Application Laid-Open No. 07-023767 discloses that an optical bioreactor in which a lamp is fixedly arranged inside a culture tank is also proposed. By disposing the lamp inside the culture tank, the culture tank does not need to be made of a transparent material, and the light can easily reach the culture solution unlike the case where light is irradiated from the outside of the culture tank.

  In JP-A-2006-014627, light from a lamp arranged outside the culture vessel is reflected inside the culture vessel so that the light can easily reach the culture solution.

  Also, according to the Nikkei Sangyo Shimbun on July 1, 2005, the photosynthesis of algae is more effective in the combination of light and dark than the light continues to strike, and the cycle of light and dark is also influenced by algae. It is stated that there is an optimal cycle. In this bright part, algae uses light energy to decompose water into hydrogen and oxygen, and at the same time, it produces a bright reaction that generates and accumulates chemical energy by the action of enzyme protein, and in the dark part, the accumulated hydrogen, chemical energy and air Using the carbon dioxide taken from the inside, it performs a dark reaction to synthesize high value-added substances such as sugars and proteins.

  Some photobioreactors can be viewed on the Internet website. In this photobioreactor, a culture solution is put between a pair of opposing culture vessel walls, and light is irradiated to the culture solution near the culture solution wall with lamps arranged on the outer wall surfaces of both walls. On the other hand, the artificial culture of algae is performed as a dark area by making it difficult for light to reach the culture solution near the middle of both wall bodies. In this photobioreactor, the culture solution is agitated to prevent the generation of algae that do not reach light when the concentration of algae increases.

  However, even if the culture solution is stirred, the concentration of algae is high, so that the culture solution that reaches the light even when the culture solution is externally irradiated (external lighting) is very close to the inner wall of the culture vessel wall. Only the portion becomes substantially light, so that the light does not reach the culture solution having a high concentration, and the efficiency becomes extremely low. Although it is necessary to increase the irradiation intensity of light to reach the light, there is a limit to the increase of the irradiation intensity, and the culture cost increases rapidly.

  On the other hand, in the internally-illuminated optical bioreactor in which the lamp is arranged inside the culture tank, the lamp is fixedly arranged, so that the light does not reach the culture solution as far as possible from the lamp, and the culture efficiency is the same as above. bad. In order to improve the culture efficiency, a large number of such lamps are arranged in the culture tank, and the culture cost is significantly increased.

In addition, the light transmission becomes worse with the growth of algae, and the culture efficiency is extremely lowered. Therefore, when a lamp is placed in the culture solution, the surface of the lamp comes into contact with the culture solution. The surface of the lamp is significantly contaminated with the culture solution, so that light is hardly irradiated from the lamp into the culture solution, and the culture becomes difficult. In such a case, the work cost increases, such as the need to clean the lamp. Therefore, in order to facilitate the cleaning work, there has been proposed one in which a rod-shaped illuminant is disposed so as to be freely inserted into and extracted from the culture solution. However, since these rod-shaped light emitters are also fixed in position, they are contaminated with the culture medium during use, requiring frequent replacement and washing.
JP 2006-014627 A JP 2002-272447 A JP 07-023767 Nikkei Sangyo Shimbun on July 1, 2005 Development and control of photosynthesis equipment: WEB page (www.yamaha-motor.co.jp/product/bio/technology/key2/index.html) 2006/07/07

  Therefore, the problem to be solved by the present invention is to enable irradiation of photosynthetic organisms such as algae with high efficiency even when the culture solution concentration is high.

  The photobioreactor according to the present invention is a photobioreactor in which a photosynthetic organism such as algae is artificially cultured in a culture solution, a culture tank that contains the culture solution, and a rotation shaft that is rotatably disposed inside the culture tank. A field emission type lamp fixed to the rotating shaft, and controlling the rotation of the rotating shaft to rotate the lamp around the rotating shaft and act as an agitator for stirring the culture solution, The intensity and lighting are controlled to irradiate the culture solution with the required intensity of light, and the blinking timing of the lamp is controlled to control the two light-dark reactions of photosynthetic organisms such as algae. Is.

  In the present invention, since the lamp moves in the culture solution with the rotation of the rotating shaft, light can be efficiently irradiated to every corner of the culture solution in the culture tank even when the concentration of algae increases. Since the culture solution can be stirred by the lamp, the algae can be irradiated with light evenly, and a large amount of photosynthetic organisms such as algae can be cultured with high efficiency.

  In the present invention, since the lamp also serves as the stirring body at the same time, it is advantageous in terms of cost compared to the case where the stirring body is provided separately from the lamp.

  In the present invention, since a field emission type lamp that does not generate heat is used as the lamp, it is not necessary to consider the lamp heat generation countermeasure, which is a problem in many methods of installing the lamp in the culture solution, and culture in a heat medium. The liquid temperature management is not affected.

  In the present invention, heat exchange with the heat medium can be performed more evenly and efficiently by stirring with a lamp.

  In the present invention, the blinking timing of the lamp can be controlled, so that the algae in the entire culture solution can be cultured in an optimal light-dark reaction cycle.

  In the present invention, the lamp rotates in synchronization with the rotation of the rotating shaft and stirs the culture solution. In other words, the lamp is placed in the culture solution and is in direct contact with the culture solution. It is less likely to be contaminated by the culture solution, and light irradiation from the lamp into the culture solution can be performed efficiently over a long period of time, enabling optimum culture.

  In the present invention having the above characteristics, it is preferable that an electric wiring is further provided on the rotating shaft so that driving power can be supplied to the lamp from the outside of the culture tank through the electric wiring.

  The lamp preferably has a transparent water-repellent film formed on the surface. The transparent water-repellent film makes the surface of the lamp less likely to be contaminated with the culture solution, so that the culture solution can be effectively irradiated with light, and the culture solution can be stirred smoothly.

  In the present invention, it is preferable to fix a plurality of lamps obliquely in the axial direction. When the lamp is fixed obliquely in the axial direction, in addition to being able to irradiate light to the whole culture solution more efficiently, the whole culture solution can be more efficiently stirred.

  In the present invention, it is preferable that the rotating shaft has a crank shape, the ramp can rotate around the rotating shaft, and can revolve by cranking the rotating shaft. With this configuration, even when the lamp length is short, the light irradiation and stirring can be performed efficiently on the culture solution.

  In the present invention, it is preferable to control the rotation speed of the lamp to the lower side in response to the increase in the concentration of the culture solution.

  The photobioreactor of the present invention can be applied regardless of whether it is a closed type or an open type.

  According to the present invention, even when the culture solution concentration becomes high, it is possible to effectively irradiate light-synthesizing organisms such as algae with high efficiency and perform optimal culture.

  Hereinafter, an optical bioreactor according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  The photobioreactor of the embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 shows a schematic configuration of the photobioreactor of the embodiment. FIG. 1A is a sectional view thereof, and FIG. 1B is a plan view thereof. FIG. 2 is a diagram showing the blinking cycle of a field emission tubular lamp (hereinafter simply referred to as “lamp”), FIG. 3 is a diagram showing time on the horizontal axis, culture medium concentration on the vertical axis, and rotational speed of the rotary shaft, and FIG. FIG.

  The photobioreactor 2 artificially cultures photosynthetic organisms such as algae with a culture solution. The photobioreactor 2 includes a cylindrical culture tank 4. The culture tank 4 accommodates the culture solution 6. The culture tank 4 has a tank wall made of a double cylinder, and a space surrounded by the inner cylinder is used as a storage space for the culture solution 6 and a space between the two cylinders is a heat medium storage space 8. A heat medium 10 is accommodated in the heat medium accommodation space 8. The heat medium storage space 8 is configured to be able to keep the culture medium 6 in a predetermined temperature range by exchanging heat with the culture medium 6 in the culture tank 4 by the internal heat medium 10. The heat medium 10 is, for example, cold water, hot water, or other heat medium. The temperature can be appropriately set and managed according to the type of photosynthetic organism such as algae to be cultured. The temperature of the heat medium 10 is controlled according to the type of photosynthetic organism such as algae. For example, the temperature of the heat medium can be managed and controlled with a low-temperature bacterium, a mesophilic bacterium, and a high-temperature bacterium. The illustration and explanation of the structure of supply and discharge of the heat medium 10 and the temperature management and control thereof are omitted.

  The rotary shaft 12 is erected on the bottom of the culture tank 4 so as to be rotatable via a bearing 14 in the center of the culture tank 4. The material of the rotating shaft 12 is not particularly limited, and may be made of metal or resin, a water repellent film may be formed on the outer peripheral surface, and a material having a small friction coefficient is selected as the material of the rotating shaft 12. Also good.

  A plurality of lamps 16 are fixed to the rotary shaft 12 at equal intervals in the axial direction and the circumferential direction. The lamps 16 are fixed at an interval of 180 degrees in the circumferential direction with respect to the axial direction of the rotary shaft 12. The number of lamps 16 is not particularly limited according to the scale of culture. The front end side of the lamp 16 extends in a straight tube shape in the radial direction with respect to the rotating shaft 12. The shape of the lamp 16 is not particularly limited, but a straight tube shape is preferable, and a curved tube shape may also be used. While the lower end side of the rotating shaft 12 is supported by the bottom part of the culture tank 4 via the water-resistant and robust sealed bearing 12 as described above, the upper end side protrudes outside the culture tank 4, and a rotary connector is provided at the projected upper end. A gear 20 having an interior 18 is fixed, and a gear 24 of a motor 22 is engaged with the gear 20. The rotary connector 18 is connected to a pulse power source 26. Various types of motors 22 and combinations and types of gears 20 and 24 can be selected as appropriate.

  The rotary shaft 12 is internally provided with wiring 28 for applying the voltage of the pulse power supply 26 to the lamp 16 via the rotary connector 18. Since the rotary connector 18 has a well-known structure, the details thereof are omitted. However, a fixed connector is provided on the pulse power source 26 side and a rotary connector is provided on the rotary shaft 12 side. The voltage of the pulse power source 26 is supplied to the lamp 16 through the contacts of both connectors. It can be applied.

  In this case, a normal DC power supply may be used instead of the pulse power supply 26, and a switch may be provided in the DC power supply so that a voltage can be applied to the lamp 16 by controlling the opening and closing of the switch.

  The control unit 30 is constituted by a microcomputer, and controls the rotation of the motor 22, the blinking cycle of the lamp 16 through the control of the pulse power supply 26, and the temperature control of the culture solution 6 by the heat medium 8.

  As shown in FIG. 2, the control unit 30 controls the pulse power source 26 to stop the lighting period T1 of the lamp 16 (the period for applying the lighting voltage to the lamp 16) and the extinguishing period T2 (the application of the lighting voltage to the lamp 16). The duty ratio can be controlled. The lighting cycle T1 is a cycle for irradiating the culture solution 6 with light to cause a bright reaction, and the turn-off cycle T2 is a cycle for causing the culture solution 6 to perform a dark reaction without irradiating light. Further, the rotation speed (stirring speed) of the lamp 16 can be controlled by controlling the magnitude of the lighting voltage for the lamp 16.

  The control of the turn-on and turn-off periods T1 and T2 is preferable for improving the culture efficiency and improving the power saving of the lighting. A culture management database corresponding to the culture contents is stored in the control unit 30 constituted by a microcomputer, and based on this database. The lighting and extinguishing periods T1 and T2 can be controlled.

  As shown in FIG. 3, the control unit 30 decreases the rotation speed of the rotating shaft 12 and decreases the stirring speed by the lamp 16 as the concentration of the culture solution 6 increases. The lamp 16 may be controlled so that the irradiation timing and the stirring effect can be further enhanced by rotating the lamp 16 in the direction of the arrow shown in FIG. 1B for a certain period and then rotating in the opposite direction. Good. By appropriately controlling the forward / reverse rotation direction of the lamp 16 in accordance with the distribution state of the culture solution concentration, the culture can be controlled more appropriately.

  As shown in FIG. 4, the lamp 16 is a field emission type lamp that emits electrons from the cathode by forming an electric field in the space between the positive and negative electrodes to excite the phosphor. More specifically, the lamp 16 is configured such that an anode 36 with a phosphor 34 and a linear cathode 38 are opposed to each other in a vacuum-sealed glass tube 32. The cathode 38 extends linearly in the longitudinal direction of the tube at the approximate center of the glass tube 32. The anode 36 is formed as a thin film of a metal such as ITO (indium oxide / tin) or aluminum by sputtering or EB vapor deposition. The phosphor 34 is formed on the anode 36 by a slurry coating method, a screen printing method, an electric perturbation method, a sedimentation method, or the like. The cathode 38 includes a conductive wire 38a and a carbon film 38b formed on the surface of the conductive wire 38a and having a number of fine protrusions on the order of nm as electron emission points. The carbon film 38b only needs to have a sharp tube shape, wall shape, or needle-like end portion that can concentrate an electric field, such as a carbon nanotube, a carbon nanowall, or a needle-like carbon film.

  Since the lamp 16 is a field emission type cold cathode, unlike the hot cathode, the phosphor 34 can be excited to emit light by emitting electrons without the need to preheat the cathode 38, so that the blinking cycle is controlled at high speed. be able to. Further, the lamp 16 is made of anhydrous silver in the glass tube 32 and is preferable to the environment unlike a mercury-containing lamp.

  The lamp 16 is of a field emission type and is preferable in that it does not generate heat and does not interfere with the temperature management necessary for optimal culture of algae and the like.

In the lamp 16, the surface of the glass tube 32 is subjected to water repellent treatment to form a water repellent film 40, thereby preventing dirt from being adhered. In addition, when forming a water-repellent film, a sol-gel film made of an oxide thin film that exhibits low-cost and efficient mechanical film strength and durability and various functions is used as a base layer, and a water-repellent film is formed on this base layer. By doing so, it may be possible to remarkably improve the wear resistance and light resistance performance, and to maintain excellent water repellency performance in the long term. The water repellent film 40 is preferably transparent and light transmissive. As a technique for forming a water-repellent film by coating a water-repellent agent, if a silazane oligomer [CF ₃ (CE ₂ ) ₇ (CH ₂ ) ₂ SiNH _3/2 ] is used as the water-repellent agent, it is transparent and highly insulating. A water-repellent film can be formed. Further, a water-repellent transparent glass can be used for the glass tube 32.

  In order to form a transparent water-repellent film, a silicon-based, for example, silicon alkoxide and a fluorine-based, for example, perfluoroalkoxide are mixed, and water, an acid, and an alcohol-based liquid are added to the mixture to obtain a sol-gel solution. . And it can form by apply | coating the sol-gel liquid uniformly on the glass tube 32 surface, and baking after drying.

  In addition, an antibacterial transparent water-repellent film having antibacterial properties, transparency comparable to glass, and water repellency comparable to that of a fluororesin is useful and preferable when used in an environment where dirt easily adheres. This antibacterial transparent water repellent film can be composed of, for example, glass mainly composed of silicon oxide, molecules having a fluoroalkyl chain, and antibacterial fine particles. Antibacterial fine particles include silver and titanium oxide.

  In the optical bioreactor 2 having the configuration described above, the control unit 30 controls the rotation of the rotating shaft 12 to rotate the lamp 16 around the rotating shaft 12 to act as a stirring body for stirring the culture solution 6; Further, the light intensity of the lamp 16 and the blinking period can be controlled to control the culture medium 6 to be irradiated with light having a required intensity and to control the light and dark reactions of the culture medium 6.

(Other embodiments)
The lamp 16 may be disposed at the same position in the circumferential direction at equal intervals in the axial direction with respect to the rotating shaft 12, as shown in the sectional view of FIG. 5A and the plan view of FIG. The lamps 16 may be arranged at an interval of 180 degrees in the circumferential direction at equal intervals in the axial direction with respect to the rotating shaft 12, as shown in the cross-sectional view of FIG. 6A and the plan view of FIG. 6B. . The lamp 16 may be disposed at an axially inclined position and at the same circumferential position with respect to the rotating shaft 12, as shown in the cross-sectional view of FIG. 7A and the plan view of FIG. 7B. As shown in the sectional view of FIG. 8 (a) and the plan view of FIG. 8 (b), the ramp 16 has a rotating shaft 12 in a crank shape, and a plurality of ramps 16 are arranged around each crank portion by a drive mechanism (not shown). It may be configured to be able to rotate and revolve around the rotation axis 12 so that the culture solution in the culture vessel 4 can be irradiated.

FIG. 1A is a sectional view of a photobioreactor according to an embodiment of the present invention, and FIG. 1B is a plan view thereof. FIG. 2 is a diagram showing the blinking cycle of the lamp. FIG. 3 is a graph showing time on the horizontal axis and the culture solution concentration and the rotation speed of the rotation axis on the vertical axis. FIG. 4 is a diagram showing the configuration of the lamp. FIG. 5A is a cross-sectional view of a photobioreactor according to another embodiment, and FIG. 5B is a plan view thereof. 6A is a cross-sectional view of a photobioreactor according to still another embodiment, and FIG. 6B is a plan view thereof. FIG. 7A is a sectional view of a photobioreactor according to still another embodiment, and FIG. 7B is a plan view thereof. FIG. 8A is a sectional view of a photobioreactor according to still another embodiment, and FIG. 8B is a plan view thereof.

Explanation of symbols

2 Photobioreactor 4 Culture tank 6 Culture solution 8 Heat medium storage tank 10 Heat medium 12 Rotating shaft 14 Bearing 16 Lamp 18 Rotary connector 20 Gear 22 Motor 24 Gear 26 Pulse power supply 28 Electric wiring 30 Controller

Claims (8)

In a photobioreactor that artificially cultures photosynthetic organisms such as algae in a culture solution,
A culture tank containing the culture solution;
A rotating shaft rotatably disposed inside the culture tank;
A field emission lamp fixed to the rotating shaft;
With
Rotating the rotating shaft and rotating the lamp around the rotating shaft to act as a stirrer that stirs the culture solution, and controls the light emission intensity and lighting of the lamp to irradiate the culture solution with the required intensity of light. In addition, the photobioreactor is characterized in that the light and dark reactions of photosynthetic organisms such as algae can be controlled by controlling the blinking timing of the lamp.   2. The photobioreactor according to claim 1, wherein an electric wiring is provided on the rotating shaft so that driving power can be supplied to the lamp from the outside of the culture tank through the electric wiring.   The photobioreactor according to claim 1, wherein a transparent water-repellent film is formed on the surface of the lamp.   The lamp has a glass tube extending in a tubular shape, an anode with a phosphor provided on the inner surface of the glass tube, and a carbon film for field emission is formed on the surface extending in the shape of a wire in the tube axis direction in the center of the glass tube. The photobioreactor according to any one of claims 1 to 3, wherein the photobioreactor comprises a wire-like cathode.   The photobioreactor according to any one of claims 1 to 4, wherein a plurality of lamps are fixed obliquely in the axial direction.   The rotary shaft has a crank shape, the ramp can rotate around the rotary shaft, and the inside of the culture tank can revolve by cranking the rotary shaft. Optical bioreactor.   The tank wall of the culture tank is formed as a double cylinder, and a space surrounded by the inner cylinder is used for accommodating a culture solution, and a space between both cylinders is used as a heat medium accommodation space. 7. The photobioreactor according to any one of 6. In a photobioreactor that artificially cultures photosynthetic organisms such as algae in a culture solution,
A culture tank containing the culture solution;
A heat medium container that forms a tank wall of the culture tank and houses a heat medium therein;
A rotating shaft rotatably disposed inside the culture tank;
A plurality of field emission lamps fixed to the rotating shaft;
A control unit for controlling the heat medium, the rotation shaft, and the lamp;
With
The rotating shaft is provided with wiring for supplying driving power to the lamp, and can supply driving power to the lamp through the wiring from outside the culture tank,
The lamp has a glass tube extending in a tubular shape, an anode with a phosphor provided on the inner surface of the glass tube, and a carbon film for field emission is formed on the surface extending in a wire shape in the tube axis direction in the center of the glass tube. A wire-like cathode,
The controller controls the rotation axis to rotate the lamp around the rotation axis to act as a stirring body for stirring the culture solution, and controls the emission intensity and lighting of the lamp to the culture solution. A photobioreactor characterized by irradiating light of a required intensity and controlling the blinking timing of the lamp to control two reactions of light and darkness of photosynthetic organisms such as algae.

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