KR100818203B1 - Cell circulating photobioreactor and culture method of photosynthetic microorganisms using the same - Google Patents

Abstract

The present invention relates to a cell circulating photobioreactor and a method for culturing photosynthetic microorganisms using the same, and more particularly, to circulate cultured cells and a culture medium, and to supply light to a relatively small volume of culture medium while producing cell growth and useful materials. It provides a cell circulating photobioreactor and a method of culturing photosynthetic microorganisms using the reactor. Unlike the vertical cylindrical photobioreactor, which supplies constant light energy from the outside, the cell circulation photobioreactor of the present invention was manufactured by separating the reactor into a first reactor and a second reactor having different sizes, and the photosynthetic microorganisms were prepared together with the culture medium. While culturing the first reactor and the second reactor to circulate, strong light energy was supplied to the second reactor having a smaller width and size than the first reactor. In the cell circulating photobioreactor of the present invention, light does not reach above a certain depth in high concentration culture, and solves the problem that light energy is inefficiently used due to the interference effect between cells. It is useful for producing photosynthetic microorganisms and useful products produced by photosynthetic microorganisms.

Photobioreactors, photosynthetic microorganisms, useful products, culture methods

Description

Split-column circulating photobioreactor and method for culturing photosynthetic microorganisms using the same

Figure 1 is a schematic diagram showing the distribution of light according to the cell concentration in the photobioreactor:

(A): low cell concentration;

(B): high cell concentration;

Left arrow: light energy supplied; And

Right arrow: Light energy passing through the culture.

FIG. 2 is a graph schematically illustrating a phenomenon in which light is distributed in FIG. 1.

3 is a schematic diagram of a cell circulating photobioreactor.

4 is a side view of a cell circulating photobioreactor.

5 is a cross-sectional view of a cell circulating photobioreactor.

6 is a graph showing the cell concentration of hematococcus cultured in a vertical cylindrical photobioreactor and a cell circulating photobioreactor:

Left value in parentheses: light energy supplied to the first reactor 1; And

Right value in parentheses: light energy supplied to the second reactor 2.

7 is a graph showing the concentration of astaxanthin produced by hematococcus cultured in a vertical cylindrical photobioreactor and a cell circulating photobioreactor:

Left value in parentheses: light energy supplied to the first reactor 1; And

Right value in parentheses: light energy supplied to the second reactor 2.

8 is a graph showing the cell concentration of hematococcus cultured in a cell circulation photobioreactor supplying light energy through blue and red LEDs.

9 is a graph showing the cell concentration of hematococcus cultured in a cell circulation superbioreactor supplying light energy through blue and red LEDs.

<Explanation of symbols for the main parts of the drawings>

1: first reactor 2: second reactor

3: culture solution inlet 4: gas outlet

5 Sampling Exit 6: First Gas Inlet

7: second gas inlet port 8: first connecting passage

9: second connection path 10: light source

11: glass tube 12: thermometer

13: entrance

The present invention relates to a cell circulating photobioreactor and a method for culturing photosynthetic microorganisms using the same.

Due to the various capabilities of the current microalgae, the use of waste water treatment, carbon dioxide immobilization, the production of fuel materials, pharmaceuticals, cosmetics, etc. has been expanded, the demand is increasing. However, development of economically and technically efficient incubators is urgently needed to produce large quantities of biomass and useful products.

There are many factors that affect the biomass and useful product increase of microalgae, such as the composition of the medium, temperature, pH, light intensity, light quantity, etc. Among them, light is the largest share due to the nature of photosynthetic microalgae. The efficiency of the light supply is an important consideration in the construction of photobioreactors.

Depending on the type of photobioreactor, in general, the larger the size of the photobioreactor, the greater the efficiency of light supply is bound to fall (see Figure 1). It is not a big problem when supplying light to low cell concentration, but light transmission is limited at high cell concentration, and even though strong light is supplied to the surface of photoreactor due to mutual shading between cells, Light is hardly reached at the center of the reactor, resulting in an unbalanced distribution of light (see FIG. 2). In particular, in the case of producing a useful product which is produced by being greatly influenced by light energy from microalgae, the above-mentioned problems may be greatly generated by supplying a lot of light energy.

Recently, various high value products derived from photosynthetic microorganisms have been developed, and various culture apparatuses for high concentration culture thereof have been developed. In warm climates and low land costs, such as in the equator, outdoor cultures in the form of ponds or raceways that circulate the medium to paddl wheels are used. While the operating cost is low, the high concentration is difficult and the possibility of contamination by other microorganisms increases the cost of separation and recovery of the target product.

In order to overcome this problem, various types of photobioreactors suitable for high concentration and mass cultivation have been developed mainly in Western countries, Japan, Israel and Australia. As widely used photobioreactors, tubular photobioreactors and thin-panel photobioreactors using sunlight as an external light source are known (Korean Patent No. 220310). The structure of the reactor maximizes the irradiation area exposed to sunlight and shortens the light transmission distance into the culture medium, so that a narrow, long rectangular or cylindrical pipe is closely packed to form a loop, and a part of the loop is raised to form an air. Characterized by having a structure that circulates the culture through the flotation.

On the other hand, in the areas where the four seasons are obvious, such as in Korea or Japan, and the land cost is high, the interior surface has a structure that can maximize the irradiation surface area per unit volume by installing a large number of optical fibers, fluorescent lamps, and light emitting diode elements as internal lights. Various types of internally radiating photobioreactors have been developed (Korean Patent No. 283026).

However, compared to the outdoor culture method of photosynthetic microorganisms using such a photobioreactor, small-capacity high concentration cultivation is advantageous, but when cultivating a large-capacity, large-scale value is difficult due to the expensive installation and operation costs due to the complexity of the reactor structure. Limited use in the production of materials.

The type of photobioreactor currently being developed in Korea is an air-lift photobioreactor using a cylindrical inner conduit as a light emitter (Korean Patent No. 283026) and a light emitting turbine using a stirrer as a light emitter. A stirred-link photobioreactor (Korean Patent Publication No. 2003-18196) is known. On the other hand, the simplest structure is suitable for cultivation of a large amount of microorganisms, and the development of technology regarding the effective supply of light energy, the temperature control and mixing of the culture medium for culturing photosynthetic microorganisms is insufficient.

The inventors divided the vertical cylindrical photobioreactor at an appropriate ratio and connected the two parts to each other to circulate the cells and the culture solution. In addition, by supplying more light energy to the second reactor having a smaller width and size than the first reactor, the above-mentioned problem of unbalanced distribution of light and inefficiency due to mutual interference between cells was solved. Through this, the present invention was completed by confirming that the overall light energy can be consumed less than when cultured in general, or that more useful products can be produced with the same amount of light energy.

It is an object of the present invention to provide a photobioreactor capable of efficiently producing photosynthetic microorganisms and useful products produced by the microorganisms by supplying a small amount of light energy, and a method of culturing photosynthetic microorganisms using the same.

In order to achieve the above object, the present invention provides a cell circulating photobioreactor capable of culturing photosynthetic microorganisms and useful products produced by the microorganisms by supplying a small amount of light energy.

The present invention also provides a method for culturing photosynthetic microorganisms using the photobioreactor.

Hereinafter, the present invention will be described in detail.

The present invention provides a photobioreactor.

The photobioreactor of the present invention is a photobioreactor having a separate first reactor 1 and a second reactor (2), the photobioreactor is capable of circulating microorganisms by a circulation device provided therein, The light source mounted on at least one of the two reactors is characterized in that the light can be irradiated to only a part of the whole microorganisms or the light at different luminous intensity to both reactors. The circulator of the photobioreactor may be of an air-lift type, but other mechanical or physical methods may be used. The light source is preferably selected from the group consisting of sunlight, fluorescent lamps, optical fibers, neon plates, light emitting diode (LED) devices, and the like. The installation of the light source includes the type of light source, the type and size of the reactor, the concentration and production of cells to be operated. It is preferable to attach it to the inside or the outside depending on the characteristics of useful materials.

In addition, the present invention provides a cell cycle photobioreactor.

The cell circulation photobioreactor of the present invention includes a first reactor (1) and a second reactor (2) of different sizes, which can accommodate photosynthetic microorganisms to be cultured; A first connection passage (8) provided at the upper end and a second connection passage (9) provided at the lower end for integrally connecting the first reactor (1) and the second reactor (2); A first gas inlet 6 provided at a lower end of the first reactor 1 for injecting gas to move cells and culture medium; An inlet 13 at the top of the first reactor equipped with an incubator inlet 3, a gas outlet 4, and a sampling inlet and outlet 5; And a light source 10 for supplying light energy to the cultured cells of the second reactor 2 (see FIG. 4).

The cell circulating photobioreactor may be manufactured in various forms, preferably selected from the group consisting of a cuboid flat plate, a cylinder, and a tubular reactor, and more preferably, a cylindrical reactor. It is not limited to this. The cell circulating photobioreactor is divided into a first reactor (1) and a second reactor (2), and the second reactor (2) of the cell circulating photobioreactor has a height and diameter greater than that of the first reactor (1). Small ones are preferable. In addition, the reactor of the photobioreactor of the present invention consists of a conical shape from a predetermined position of the lower outer surface to the lower end (see Fig. 3).

The height of the first reactor 1 of the cell circulation photobioreactor of the present invention is preferably 500 to 600 mm, the diameter is 80 to 90 mm, the height of the second reactor is 400 to 500 mm, the diameter is 40 to 50 Preferably, mm is not limited thereto, and the width and diameter of the reactor may be made larger according to the desired amount of useful product obtained (see FIG. 4).

The first reactor 1 of the cell circulating photobioreactor may have an inlet 13, and not only the first reactor 1 but also the second reactor 2 may have an inlet 13, but is not limited thereto. It doesn't happen. The inlet 13 of the first reactor 1 or the second reactor 2 of the cell circulation photobioreactor is provided with a cell and a culture medium through a culture medium inlet 3, a gas outlet 4, and a sampling inlet 5. It was made to inject and release the gas. In addition, the inlet 13 of the first reactor 1 may be provided with a glass tube 11 for installing an internal light source (see FIG. 5).

The first reactor 1 and the second reactor 2 of the cell circulation photobioreactor are designed to be integrated through the first and second connection passages 8 and 9 provided at the top and the bottom thereof. Provides a passage through which cells and cultures can circulate within the reactor. The length of the first connection passage 8 provided at the top is preferably 10 to 30 mm, the diameter is 10 to 20 mm, but is not limited thereto. The length of the second connection passage 9 provided at the bottom is preferably 30 to 80 mm, the diameter is 5 to 15 mm, but is not limited thereto. It is preferable that the second connecting passage 9 provided at the bottom is inclined from the second reactor 2 toward the first reactor 1.

A second connection connecting the first reactor 1 and the second reactor 2 to the side surface of the first gas inlet 6 provided at the bottom of the first reactor 1 to move the cells to the photobioreactor. When the passage 9 is connected and the gas is supplied through the second gas inlet 6 provided at the bottom of the first reactor 1, the culture solution of the second incubator 2 is automatically supplied by the pressure difference. Sucked into (1). The second connecting passage 9 provided at the bottom connecting the first reactor 1 and the second reactor 2 is inclined from the second reactor 2 toward the first reactor 1 so that only the gas injection is naturally applied. Culture medium can be moved to the reactor (1). In addition, since the first connecting passage 8 provided at the top of the reactor does not have a driving force to move the cells like the second connecting passage 9 provided at the bottom, the second connecting passage provided at the bottom ( Unlike 9), the first connection passage 8 provided at the upper end of the connection site was made wider (about 10 mm in diameter) to smoothly move the cells and the culture medium spontaneously. As mentioned above, the movement between the two reactors may use other mechanical or physical methods.

In addition, the second gas inlet 7 of the cell circulating photobio-incubator may be additionally installed. In order to prevent the precipitation of cells during the culture, gas was injected into the second gas inlet 7 provided at the bottom of the second reactor 2 to incubate photosynthetic microorganisms (see FIG. 3).

The light source of the present invention can be attached to the inside or outside of the second reactor 2. When the light source is installed inside, the efficiency of light increases, but there may be heat generation and spatial problems. Therefore, the shape and size of the reactor, the type of light source, the type and concentration of cells to be operated, the concentration of the material to be produced, It can be installed externally or internally in consideration of production volume. The light source of the present invention is not particularly limited thereto, but is preferably selected from the group consisting of sunlight, fluorescent lamps, optical fibers, neon plates, light emitting diode (LED) devices, and the like. In addition, the photobioreactor of the present invention is preferably provided with a light source in the interior of the first reactor (1). The light source installed in the first reactor 1 is more preferably using a blue light emitting diode (LED) device or a red light emitting diode (LED) device, but is not limited thereto. The light source 10 installed in the second reactor 2 is preferably provided with a fluorescent lamp as an external light source, but is not limited thereto (see FIG. 3). The cell circulation photobioreactor of the present invention supplies a lot of light energy to the second reactor 2 which is smaller in height and diameter than the first reactor 1.

In general, the biggest consideration in manufacturing a photobioreactor is how to supply light energy, and the supply and distribution of light energy is the most important factor for culturing cells or obtaining desired useful products. However, photosynthetic mechanisms and mechanisms are very sensitive to light absorption and scattering, so even if the light is supplied from the outside at a high level, the light energy absorbed by the cells inside the reactor is relatively higher than that of the reactor surface. Low level. Considering the light transmission surface in actual cell culture, when the cells are at a concentration of 5 × 10 ⁵ cells / ml or more, the light does not penetrate 2 cm of the culture solution. In order to solve this problem, the photobioreactor of the present invention is manufactured by separating the first reactor 1 and the second reactor 2, and in particular, the second reactor 2 takes into account the light transmittance of the first reactor 1 By making it smaller than) but by supplying a large amount of light energy by installing a light source, the cells entering the second reactor 2 can be equally supplied with light energy. In addition, by allowing the microbial culture to circulate in the first reactor (1) and the second reactor (2) to ensure that all the cells in the reactor is equally light, and to minimize the mutual interference effect between the cells.

The present inventors produced the cell-circulating photobioreactor and cultured hematococcus which is one of the green algae. As a control, a conventional vertical cylindrical photobioreactor was used. We supplied 39 μE / s light energy to the control and 7 (0: 7), 15 (0:15), 48 (33:15), 70 (0:70) μE / to the cell cycle photobioreactor. s (light energy supplied to the first reactor (1): light energy supplied to the second reactor (2)) Useful for supplying light energy and culturing hematococcus for 42 days to produce cell concentration and hematococcus The concentration of the product astaxanthin was measured. Astaxanthin is derived from cells by high light, and its mechanism is known to be produced to protect cells from exposure to high light. As a result, 4.9 × 10 ⁵ cells / mL were obtained for the control, and 4.3 × 10 ⁵ cells / mL, 3.9 × 10 ^{5 for the} cell circulating photobioreactor (light energy: 7, 15, 48, 70 μE / s). Cells / ml, 4.5 × 10 ⁵ cells / ml, 4.4 × 10 ⁵ cells / ml (see Table 1 and FIG. 6). The concentration of astaxanthin, a useful product, was 185 mg / l in the control and 117 mg / l, 165 mg / l, 251 mg / l and 224 mg / l in the cell cycle photobioreactor, respectively (Table 1 and See FIG. 7). Comparing the cell concentration and the astaxanthin concentration of the cell circulating photobioreactor with the control, the values are similar, but compared with the light energy supplied, the cell circulating photobioreactor of the present invention shows less light energy than the control. The production of useful products can be efficiently cultivated while consuming. The present inventors incubated hematococcus by appropriately distributing light energy to the first reactor 1 and the second reactor 2 of the cell circulation photobioreactor. The cell circulation photobioreactor supplied 3.4 μE / s light energy using a blue LED or a red LED to the first reactor 1 as an internal light, and a light energy supply device 10 to the second reactor 2. 15 μE / s light energy. Control 1 supplied 33 μE / s light energy to the vertical cylindrical photobioreactor, and control 2 supplied 18.4 μE / s light energy to the vertical cylindrical photoreactor. As a result, the cell concentration of Control 1 was 4.98 × 10 ⁵ cells / ml, the Control 2 cell concentration was 4.33 × 10 ⁵ cells / ml, and the cell concentration of the cell circulating photobiotic cell using blue LED was 4.28 × 10 ^5. The cell concentration of the cell circulating photobiotic cell phase using cells / ml and red LED was 4.63 × 10 ⁵ cells / ml , and there was no significant change in the cell concentration of the control and cell circulating photobiological cell phase (see FIG. 8). Astaxanthin concentration was measured as a control 1 produced 188 mg / L, and control 2, which supplied the same light energy as the cell circulating photobiological cell produced 124 mg / l. Cell circulating photobiotic cell produced 180 mg / l when using blue LED as the internal illumination in the first reactor 1, and produced 175 mg / l astaxanthin when using red LED (FIG. 9). Reference). When the same amount of light energy was used, the cell circulating photobiological cell group showed higher concentration of astaxanthin than the vertical cylindrical photobiological cell group, similar to that of the vertical cylindrical optical cell reactor which supplied higher light energy. By showing the chitin production concentration, the cell cycle photobioreactor of the present invention was found to exhibit high productivity even when the same light energy was supplied to produce useful products and biomass from photosynthetic microorganisms.

The present invention provides a method for culturing photosynthetic microorganisms using the cell cycle photobioreactor.

The present invention provides a method for culturing photosynthetic microorganisms as follows: 1) culturing photosynthetic microorganisms using a photobioreactor that supplies constant light energy from the outside; 2) injecting the photosynthetic microorganism cultured in step 1) into the cell circulation photobioreactor of the present invention; 3) supplying light energy to only part of the cell circulation photobioreactor or supplying light energy of different luminosity to both photobioreactors and circulating the culture to increase the biomass and useful product of photosynthetic microorganisms; And 4) harvesting the culture solution of step 3) to obtain useful products of photosynthetic microorganisms.

Step 1) aims to increase the cell concentration of photosynthetic microorganisms, while supplying strong light energy through a light source while culturing the photosynthetic microorganisms cultured in step 1) in the cell circulation photobioreactor of the present invention in step 2). Useful products can be produced. In the present invention, the cell concentration was increased by culturing hematococcus in step 1), and astaxanthin, a useful product, was induced through excessive light through step 2).

In the above method, step 1) may be omitted depending on the type of photosynthetic microorganism and the purpose of culture. If the purpose of cultivation of a person skilled in the art is high concentration culture of photosynthetic microorganisms, it may be cultured directly in the cell circulation photobioreactor of step 2) without going through step 1). However, if the purpose of cultivation of those skilled in the art is a useful product produced by photosynthetic microorganisms induced by light energy, it is preferable to go through step 1).

In the above method, the photosynthetic microorganism of step 1) may be cultured selected from the group consisting of hematococcus, dunaellia, chlorococum, chlorella, acetabularia, microsistis, tostock and oscillatoria. However, it is not limited thereto.

In the above method, the method for obtaining the useful product of the photosynthetic microorganism of step 4) is not particularly limited, and methods known to those skilled in the art may be used.

Hereinafter, the present invention will be described in more detail with reference to Examples.

However, the following examples are merely to illustrate the present invention, and the contents of the present invention are not limited to the following examples.

< Example  1> cell circulation Photobioreactor and  Vertical cylindrical In photobioreactors  Comparison of Concentrations of Useful Products

The inventors have used Haematococcus ( Haematococcus ) using a cell cycle photobioreactor (2.5 L) and a vertical cylindrical photobioreactor (2.5 L). production of astaxanthin from pluvliais ). For this, 39 μE / s of light energy was supplied to the vertical cylindrical photobioreactor, and 7 (0: 7), 15 (0:15), 48 (33:15), 70 (0: 70) Hematococcus was cultured by supplying various light energies with μE / s (light energy supplied to the first reactor 1: light energy supplied to the second reactor 2). As the culture conditions, the medium was MBBM, the culture temperature was maintained at 25 ℃, the cell number was measured precisely using a Coulter counter.

As a result, the maximum concentration cultured in the photobioreactor of the control was 4.9 × 10 ⁵ cells / ml, and in the cell circulating photobioreactor (light 7, 7, 15, 48, 70 μE / s), respectively, 4.3 × 10 ⁵ cells / ML, 3.9 × 10 ⁵ cells / mL, 4.5 × 10 ⁵ cells / mL, 4.4 × 10 ⁵ cells / mL, were obtained (FIG. 6). In addition, the concentration of astaxanthin, a useful product, was 185 mg / l in the control and 117 mg / l, 165 mg / l, 251 mg / l and 224 mg / l in the cell cycle photobioreactor, respectively. The concentration of astaxanthin at low light levels was lower than that of the control, but the cell circulation photobioreactor showed high efficiency when comparing the amount of light supplied with the efficiency of astaxanthin (Table 2 and FIG. 7).

The amount of light energy supplied (μE / s) Maximum concentration of cultured cells Astaxanthin Concentration (mg / L) Large side reactor Small side reactor Vertical Cylindrical Photobioreactor 39 4.9 × 10 ⁵ cells / ml 185 Cell cycle photobioreactor 0 7 4.3 x 10 ⁵ cells / ml 117 0 15 3.9 × 10 ⁵ cells / ml 165 33 15 4.5 x 10 ⁵ cells / ml 251 0 70 4.4 × 10 ⁵ cells / ml 224

< Example  2> Cell circulation due to efficient light distribution In photobioreactors  Increased incubation time and astaxanthin concentration.

In Example 1, the cell circulating photobioreactor showed an efficient way to produce astaxanthin per light energy. Then, 15 μE / s of light energy is supplied to the smaller photobioreactor, which is supplied with a relatively large amount of light energy, to increase astaxanthin through proper distribution of light energy, and to the larger photobioreactor. In order to increase the efficiency of the blue and red LEDs (light emitting diodes, 3.4 μE / s) was used as an internal light source. In addition, the experiment was performed with a supply of 33 μE / s externally as control 1 and 18.4 μE / s such as the total amount of light entering the cell circulating photobioreactor as control 2 was supplied from the outside of the photobioreactor.

As a result, the total concentration of cells showed a similar tendency in all four (Fig. 8). In addition, the concentration of astaxanthin, a useful product, was about half that of light energy when compared to control 1 (188 mg / l), but the concentration of astaxanthin was lower than that of control 1 Similar concentrations (blue LED: 180 mg / l, red LED: 175 mg / l) were shown (Table 2 and FIG. 9). In addition, when comparing the concentration of astaxanthin in control 2 (124 mg / ℓ) and the cell cycle photobioreactor with the same amount of light, the blue and red LEDs showed 168% and 164% increase respectively. .

In addition, when comparing the amount of light supplied with the efficiency of astaxanthin, it was found that the cell cycle photobioreactor increased the light energy efficiency by 168% and 164%, respectively, compared to Control 1, and compared with Control 2. Was increased to 142% and 142%.

Through this, the cell cycle photoreactor showed high productivity with the same light energy in producing useful products and biomass from photosynthetic microorganisms.

The amount of light energy supplied (μE / s) Maximum concentration of cultured cells Astaxanthin Concentration (mg / L) First reactor (1) Second reactor (2) Vertical Cylindrical Photobioreactor Control 1 33 4.98 × 10 ⁵ cells / ml 188 Control 2 18.4 4.33 × 10 ⁵ cells / ml 124 Cell cycle photobioreactor Blue LED 3.4 15 4.28 × 10 ⁵ cells / ml 180 Red LED 3.4 15 4.63 × 10 ⁵ cells / ml 175

The cell circulation photobioreactor of the present invention is manufactured by separating the reactor into a first reactor 1 and a second reactor 2 having different sizes, unlike a vertical cylindrical photobioreactor that supplies constant light energy from the outside. While microorganisms were cultured to circulate the first reactor 1 and the second reactor 2 together with the culture medium, strong light energy was supplied to the second reactor 2 having a smaller width and size than the first reactor 1. Accordingly, the photobioreactor of the present invention minimizes the interference effect between cells by shortening the transmission distance of light, and can efficiently produce useful products because all cells are equally supplied with light energy through cell circulation. The cell circulation photobioreactor of the present invention significantly and economically improves the method of supplying light energy that takes up the largest proportion when producing photosynthetic microorganisms, and thus produces photosynthetic microorganisms and photosynthetic microorganisms using the same or less amount of light energy. Useful for producing useful products.

Claims (14)

In a photobioreactor having a separate first reactor (1) and second reactor (2), the height and diameter of the second reactor is smaller than the height and diameter of the first reactor, the circulation device provided therein It is possible to circulate between the first reactor and the second reactor of the microorganisms, and to emit light to only a part of the whole microorganisms by the light source mounted in the second reactor or both reactors, Photobioreactor which can be irradiated. The photobioreactor of claim 1, wherein the circulation device is an air-lift type. The photobioreactor of claim 1, wherein the light source is selected from the group consisting of sunlight, fluorescent lamps, optical fibers, neon plates, and light emitting diode (LED) devices. The photobioreactor of claim 1, wherein the light source is attached inside or outside according to the type of light source, the shape and size of the reactor, the concentration of the cells to be operated, and the characteristics of the useful materials produced. The method of claim 1, A first reactor (1) capable of accommodating photosynthetic microorganisms to be cultured and a second reactor (2) having a smaller height and diameter than the first reactor; A first connection passage (8) provided at the upper end and a second connection passage (9) provided at the lower end for integrally connecting the first reactor (1) and the second reactor (2); A first gas inlet 6 provided at a lower end of the first reactor 1 for injecting gas to move cells and culture medium; An inlet 13 above the first reactor 1 having a culture medium inlet 3, a gas outlet 4, and a sampling outlet 5; And Cell circulation photobioreactor comprising a light source (10) for supplying light energy to the cultured cells of the second reactor (2). delete 6. The cell according to claim 5, wherein the shape of the first reactor 1 and the second reactor 2 is selected from the group consisting of a cuboid flat plate, a cylinder and a tubular reactor. Circulating photobioreactor. 6. The cell circulation photobioreactor according to claim 5, wherein a glass tube (11) is provided at the inlet (13) of the first reactor (1) for installing an internal light source. 6. The cell circulation photobioreactor according to claim 5, wherein the cell-shaped photobioreactor is formed in a conical shape from a predetermined position to a lower end of the lower outer surfaces of the first reactor and the second reactor. 6. The cell circulation photobioreactor according to claim 5, wherein the second reactor (2) is supplied with more light energy through the light source than the first reactor (1). 1) culturing the photosynthetic microorganism using a photobioreactor for supplying constant light energy from the outside; 2) injecting the photosynthetic microorganism cultured in step 1) into the cell circulating photobioreactor of claim 1; 3) supplying light energy to only a part of the cell circulation photobioreactor or supplying light energy of different luminosity in both photobioreactors and circulating the culture to increase the biomass and useful product of photosynthetic microorganisms; And 4) A method for culturing photosynthetic microorganisms, comprising harvesting the culture medium of step 3) to obtain useful products of photosynthetic microorganisms. 12. The method of culturing photosynthetic microorganisms according to claim 11, wherein a part of step 3) is a second reactor (2). The method of culturing photosynthetic microorganisms according to claim 11, wherein the circulation of the culture solution in step 3) is performed by supplying a gas. 12. The method of claim 11, wherein the photosynthetic microorganism comprises haematococcus, dunaellia, chlorococum, chlorella, acetabularia, microcystis, tostock and oscillatoria.

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