JP2017079602A - Culture apparatus and culture method of photosynthetic microorganism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a culture apparatus and a culture method of a photosynthetic microorganism which do not necessarily require a complicated structure, and in which the microorganism can be easily cultured.SOLUTION: A culture apparatus 1 of a photosynthetic microorganism comprises: agitation units 5,7 which agitate culture solution 17 in a culture tank 3 installed outdoors; an oxygen concentration detection unit 11 which detects dissolved oxygen concentration in the culture solution; a temperature detection unit 9 which detects the temperature of the culture solution; a saturated concentration calculation unit 25 which calculates the saturated concentration of oxygen in the culture solution at the temperature detected by the temperature detection unit; and an agitation control unit 27 which stops agitation by the agitation unit at least in a partial stop period out of a period in which the dissolved oxygen concentration detected by the oxygen concentration detection unit is the saturated concentration calculated by the saturated concentration calculation unit or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a culture apparatus and a culture method for photosynthetic microorganisms.

  When photosynthetic microorganisms are cultured in an outdoor tank, predatory organisms that prey on the photosynthetic microorganisms may enter the tank. The technique described in Patent Document 1 holds a suspension containing photosynthetic microorganisms in a flat pond during the day and transfers it to a storage tank closed to the outside during the night. The technique described in Patent Document 1 kills predatory organisms by placing the inside of the storage tank in an oxygen deficient state.

Japanese Patent Laid-Open No. 6-90735

The technique described in Patent Document 1 requires a complex culture apparatus including a flat pond and a storage tank. Moreover, the technique of patent document 1 requires the transfer of the suspension between a plane pond and a storage tank.
The present invention has been made in view of these problems, and an object of the present invention is to provide a culture apparatus and a culture method for photosynthetic microorganisms that can be easily cultured without necessarily requiring a complicated structure.

  The photosynthetic microorganism culturing apparatus of the present invention includes a stirring unit that stirs a culture solution in a culture tank installed outdoors, an oxygen concentration detection unit that detects a dissolved oxygen concentration in the culture solution, and a temperature of the culture solution. A temperature detection unit, a saturation concentration calculation unit for calculating a saturation concentration of oxygen in the culture solution at a temperature detected by the temperature detection unit, and a saturation calculated by the saturation concentration calculation unit for the dissolved oxygen concentration detected by the oxygen concentration detection unit. A stirring control unit that stops stirring by the stirring unit in at least a part of the stop period of the period that is equal to or lower than the concentration;

  In the apparatus for culturing photosynthetic microorganisms of the present invention, at least a part of the period in which the dissolved oxygen concentration in the culture solution is equal to or lower than the saturation concentration is set as the stop period. The culture apparatus for photosynthetic microorganisms of the present invention stops stirring of the culture solution during the stop period. As a result, the dissolved oxygen concentration in the culture solution at night falls. As a result, the growth of predatory organisms in the culture solution can be suppressed or the predatory organisms can be killed.

  In addition, the photosynthetic microorganism culturing apparatus of the present invention can suppress the growth of predatory organisms in the culture solution or kill the predatory organisms without necessarily providing a plurality of tanks. In addition, the photosynthetic microorganism culture apparatus of the present invention can suppress the growth of predatory organisms in the culture solution or kill the predatory organisms without necessarily transferring the culture solution to another tank.

  The method for culturing photosynthetic microorganisms of the present invention is a method for culturing photosynthetic microorganisms that stirs a culture solution in a culture tank installed outdoors, and at least during a period in which the dissolved oxygen concentration in the culture solution is equal to or lower than a saturated concentration Stop the agitation of the culture medium during some stop periods.

  In the method for culturing photosynthetic microorganisms of the present invention, at least a part of the period in which the dissolved oxygen concentration in the culture solution is equal to or lower than the saturation concentration is set as the stop period. In the method for culturing photosynthetic microorganisms of the present invention, the stirring of the culture solution is stopped during the stop period. As a result, the dissolved oxygen concentration in the culture solution at night falls. As a result, the growth of predatory organisms in the culture solution can be suppressed or the predatory organisms can be killed.

  Further, in the method for culturing photosynthetic microorganisms of the present invention, the growth of predatory organisms in the culture solution can be suppressed or the predatory organisms can be killed without necessarily providing a plurality of tanks. In the method for culturing photosynthetic microorganisms of the present invention, the growth of predatory organisms in the culture solution can be suppressed or the predatory organisms can be killed without necessarily transferring the culture solution to another tank.

2 is an explanatory diagram illustrating a configuration of a culture apparatus 1. FIG. 2 is a side view showing the configuration of a culture tank 3, a water thermometer 9, and a dissolved oxygen concentration sensor 11. FIG. 3 is a block diagram illustrating a functional configuration of a control unit 15. FIG. It is a flowchart showing the process which the control part 15 performs. It is a graph showing the operation | movement state in the culture apparatus 1, and transition of DO. It is a graph showing transition of DO. It is a flowchart showing the process which the control part 15 performs. It is a graph showing the operation | movement state in the culture apparatus 1, and transition of DO. It is a flowchart showing the process which the control part 15 performs. It is a graph showing the transition of DO in the case where the cell density _{OD 720} was 0.8.

Embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
1. Configuration of Culture Device 1 The configuration of the culture device 1 will be described with reference to FIGS. The culture apparatus 1 is an apparatus for use in culturing photosynthetic microorganisms. A photosynthetic microorganism means a microorganism that produces substances such as oil and hydrocarbons from light energy and carbon dioxide. Photosynthetic microorganisms also include photosynthetic bacteria. As shown in FIG. 1, the culture apparatus 1 includes a culture tank 3, a stirring paddle 5, a drive motor 7, a water temperature meter 9, a dissolved oxygen concentration sensor 11, a photon meter 13, and a control unit 15.

  The culture tank 3 is a raceway type tank installed outdoors. The culture tank 3 contains the culture solution 17 therein. The upper part of the culture tank 3 is open, and the culture solution 17 is in contact with the outside air. If the weather is fine, sunlight enters the culture solution 17. The culture solution 17 contains photosynthetic microorganisms.

  The stirring paddle 5 is rotatably attached to the culture tank 3. A part of the stirring paddle 5 is immersed in the culture solution 17. The stirring paddle 5 is driven by a drive motor 7 and rotates. The culture solution 17 is stirred by the rotation of the stirring paddle 5. In addition, the rotation of the stirring paddle 5 causes the culture solution 17 to flow around the culture tank 3. In addition, oxygen is taken into the culture solution 17 by the rotation of the stirring paddle 5.

  The water temperature gauge 9 is attached to the culture tank 3. The water thermometer 9 detects the temperature of the culture solution 17 and sends a detection signal to the control unit 15. As shown in FIG. 2, the detection unit 9 </ b> A in the water temperature gauge 9 is located near the bottom surface 19 in the culture tank 3. Therefore, the water thermometer 9 detects the temperature of the portion of the culture solution 17 near the bottom surface 19. When a later-described deposit layer 29 is formed in the culture solution 17, the water thermometer 9 detects the temperature in the deposit layer 29.

  The dissolved oxygen concentration sensor 11 is attached to the culture tank 3. The dissolved oxygen concentration sensor 11 detects the dissolved oxygen concentration (hereinafter referred to as DO) in the culture solution 17 and sends a detection signal to the control unit 15. The detection part 11A in the dissolved oxygen concentration sensor 11 is located near the bottom surface 19 as shown in FIG. Therefore, the dissolved oxygen concentration sensor 11 detects DO in the portion of the culture solution 17 near the bottom surface 19. When a deposition layer 29 described later is formed in the culture solution 17, the dissolved oxygen concentration sensor 11 detects DO in the deposition layer 29.

The photon meter 13 is installed in the vicinity of the culture tank 3. The photon meter 13 detects the brightness at that position and sends the detection signal to the control unit 15.
The control unit 15 is mainly configured by a known microcomputer having a CPU 21 and a semiconductor memory (hereinafter referred to as a memory 23) such as a RAM, a ROM, and a flash memory.

  Various functions of the control unit 15 are realized by the CPU 21 executing a program stored in a non-transitional physical recording medium. In this example, the memory 23 corresponds to a non-transitional tangible recording medium that stores a program. Further, by executing this program, a method corresponding to the program is executed. The number of microcomputers constituting the control unit 15 may be one or plural.

  As shown in FIG. 3, the control unit 15 includes a saturated concentration calculation unit 25 and an agitation control unit 27 as a function configuration realized by the CPU 21 executing the program. The method of realizing these elements constituting the control unit 15 is not limited to software, and some or all of the elements may be realized using hardware that combines a logic circuit, an analog circuit, and the like.

  The stirring paddle 5 and the drive motor 7 correspond to a stirring unit. The dissolved oxygen concentration sensor 11 corresponds to an oxygen concentration detection unit. The water thermometer 9 corresponds to a temperature detection unit. The photon meter 13 corresponds to a sunset detection unit and a sunrise detection unit.

2. Culture Method Performed by Culture Device 1 The culture method performed by the culture device 1 will be described with reference to FIGS. When performing the culture method, the culture solution 17 is stored in the culture tank 3. The culture solution 17 contains photosynthetic microorganisms. The photosynthetic microorganism is Pseudococcomyxa sp. KJ of Trevoxia algae.

  Pseudocomicusa sp. KJ was commissioned on June 4, 2013 to the National Institute for Product Evaluation Technology Patent Biological Deposit Center (NITE-IPOD) (Room 2-5-8 Kazusa Kamashichi, Kisarazu City, Chiba Prefecture) Deposited under the number FERM P-22254. Later, on June 2, 2015, it was transferred to an international deposit. The international accession number is FERM BP-22254.

The culture solution 17 may contain predatory organisms regardless of the intention of the user of the culture apparatus 1. Examples of predatory organisms include ciliates, flagellates, and amoeba. The cell concentration OD ₇₂₀ of the photosynthetic microorganism is 1.0 at the stop period described later.

The culture method described below is controlled by the control unit 15. The control unit 15 repeats the process shown in FIG. 4 at predetermined time intervals.
In step 1, the stirring control unit 27 determines whether or not the current time is in the stop period. The stop period means a period in which the stirring paddle 5 is stopped and the culture solution 17 is not stirred. The stop period starts at step 8 described later and ends at step 12 described later. The control unit 15 rotates the stirring paddle 5 except during the stop period.

If the current time is not in the stop period, the process proceeds to step 2. If the current time is in the stop period, the process proceeds to step 9.
In step 2, the stirring control unit 27 determines whether or not the current time is night. Night means the period from sunset to sunrise. The agitation control unit 27 determines that the current time is nighttime when the brightness detected using the photon meter 13 is less than or equal to a preset threshold, and otherwise determines that the current time is not nighttime. If it is determined that the current time is night, the process proceeds to step 3. If it is determined that the current time is not night, the process is terminated.

In step 3, the agitation control unit 27 acquires the dissolved oxygen concentration (hereinafter referred to as DO) in the culture solution 17 using the dissolved oxygen concentration sensor 11.
In step 4, the stirring control unit 27 compares the DO acquired in the previous step 3 with the DO acquired in the previous step 3. If the former is lower than the latter, the process proceeds to step 5. If the former is greater than or equal to the latter, the present process is terminated. Note that the case where the DO acquired at the previous step 10 is lower than the DO acquired at the previous step 10 corresponds to a state where the DO is descending as time passes.

In step 5, the stirring control unit 27 acquires the temperature of the culture solution 17 using the water thermometer 9.
In step 6, the saturation concentration calculation unit 25 calculates the oxygen saturation concentration (hereinafter referred to as saturation DO) in the culture solution 17 at the temperature obtained in step 5. The saturation concentration calculation unit 25 is provided with a map that associates the temperature of the culture solution 17 with the saturation DO in advance, and calculates the saturation DO by inputting the temperature acquired in step 5 to the map.

  In step 7, the stirring control unit 27 determines whether or not the DO acquired in step 3 matches the saturated DO calculated in step 6. Here, “matching” includes not only a case where DO and saturation DO completely match, but also a case where the difference between the two is equal to or less than a preset threshold value. If DO matches with saturated DO, the process proceeds to step 8; if DO does not match with saturated DO, this process ends.

  In step 8, the stirring control unit 27 starts a stop period. That is, the stirring paddle 5 that has been rotating until then is stopped. The stop period continues until step 12 described later is executed.

  On the other hand, if a negative determination is made in step 1, the process proceeds to step 9. In step 9, the stirring control unit 27 determines whether or not the current time is after sunrise. The agitation control unit 27 determines that the current time is after sunrise when the brightness detected using the photon meter 13 is equal to or greater than a preset threshold value. Otherwise, the current time is still before sunrise. It is judged that. If it is determined that the current time is after sunrise, the process proceeds to step 10. If it is determined that the current time is still before sunrise, the present process is terminated.

In step 10, the agitation control unit 27 acquires DO using the dissolved oxygen concentration sensor 11.
In step 11, the agitation control unit 27 compares the DO acquired in the immediately preceding step 10 with the DO acquired in the previous step 10. If the former is higher than the latter, the process proceeds to step 12. If the former is equal to or less than the latter, the process is terminated. Note that the case where the DO acquired at the previous step 10 is higher than the DO acquired at the previous step 10 corresponds to a state where the DO is rising over time.

In step 12, the stirring control unit 27 ends the stop period that has been continued until then. After this time, the stirring paddle 5 rotates.
3. FIG. 5 shows the transition of the operation state and the DO of the culture apparatus 1 when the culture method described above is performed. Prior to sunset, the stirring paddle 5 is rotating. Before sunset, DO is higher than saturated DO. This is because the photosynthetic microorganisms generate oxygen in the culture solution 17 by photosynthesis, and oxygen is taken into the culture solution 17 by the rotation of the stirring paddle 5. When the stirring paddle 5 is rotating, the later-described deposited layer 29 is not formed.

After sunset, DO falls. This is because photosynthesis by the photosynthetic microorganisms stops and the photosynthetic microorganisms and predators respire.
After sunset, when the DO falls and coincides with the saturated DO, the stop period is started. T ₁ in FIG. 5 represents the start time of the stop period. After the start of the stop period, DO falls more rapidly. This is because oxygen uptake due to rotation of the stirring paddle 5 is lost. Further, since the rotation of the stirring paddle 5 is stopped, a deposition layer 29 containing photosynthetic microorganisms and predatory organisms is formed on the bottom surface 19 as shown in FIG. In the sedimentary layer 29, the photosynthetic microorganisms and predators that exist at high density respire, so the DO is even lower.

Throughout the night, DO remains low. After sunrise, DO rises. This is because the photosynthetic microorganism begins to generate oxygen in the culture solution 17 by photosynthesis. When DO rises after sunrise, the stop period ends. T ₂ In FIG. 5 represents the end time of the stop period. After the stop period, since oxygen is taken into the culture solution 17 by the rotation of the stirring paddle 5, DO rises more rapidly and exceeds the saturated DO. After the end of the stop period, the photosynthetic microorganisms and predators are uniformly dispersed in the culture solution 17, and the deposited layer 29 disappears.

  In FIG. 6, transition of DO when the culture method of this embodiment is implemented is shown. In addition, FIG. 6 shows a transition of DO when the stirring paddle 5 is continuously rotated regardless of day or night as a comparative example. In FIG. 6, “with a stop period” corresponds to the culture method of the present embodiment, and “continuous stirring” corresponds to the case where the stirring paddle 5 is continuously rotated regardless of day and night. When the culture method of this embodiment was implemented, DO at night could be further reduced as compared with the comparative example.

4). Effects produced by the culture apparatus 1 and the culture method (1A) The culture apparatus 1 sets a part of a period during which DO is equal to or lower than the saturated DO as a stop period. The culture apparatus 1 stops stirring by the stirring paddle 5 during the stop period. Thereby, DO at night falls further compared with the case where stirring is always performed. As a result, the growth of predatory organisms can be suppressed or the predatory organisms can be killed.

  (1B) The culture apparatus 1 can suppress the growth of predatory organisms or kill the predatory organisms without necessarily including a plurality of tanks. Moreover, the culture apparatus 1 does not necessarily need to transfer the culture solution 17 to another tank, but can suppress the growth of predatory organisms or kill the predatory organisms.

  (1C) The culture apparatus 1 starts a stop period when DO falls from a value equal to or higher than the saturated DO to the saturated DO. Thereby, DO at night falls further. As a result, the growth of the predatory organisms can be further suppressed, or the predatory organisms can be killed earlier.

(1D) The culture apparatus 1 ends the stop period when DO starts to rise. Thereby, the proliferation of photosynthetic microorganisms can be promoted.
(1E) The culture apparatus 1 uses the photon meter 13 to detect that the current time is after sunset. Then, after detecting that it is after sunset, the stop period is started. Thereby, it is possible to prevent the stop period from being erroneously started before sunset.

  (1F) The culture apparatus 1 uses the photon meter 13 to detect that the current time is after sunrise. Then, after detecting that it is after sunrise, the stop period ends. As a result, it is possible to prevent the stop period from being ended accidentally before sunrise.

(1G) In the culture method of the present embodiment, the cell concentration OD ₇₂₀ in the culture solution 17 is 1.0. Thereby, DO at night falls further. As a result, the growth of the predatory organisms can be further suppressed, or the predatory organisms can be killed earlier.

(1H) In the culture method of the present embodiment, DO and temperature are measured in the deposition layer 29 generated during the stop period. Thereby, DO and temperature in a place where many predatory organisms exist can be measured.
Second Embodiment
1. Differences from the First Embodiment Since the basic configuration of the second embodiment is the same as that of the first embodiment, description of the common configuration will be omitted, and differences will be mainly described. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  When performing the culture method in 2nd Embodiment, the control part 15 repeats the process shown in FIG. 7 for every predetermined time. Steps 21 to 31 in FIG. 7 are the same as steps 1 to 11 in the first embodiment.

  In step 32, the stirring control unit 27 determines whether or not the DO acquired in step 30 is equal to or greater than a preset threshold value T. The threshold T is a value larger than 0 and smaller than the saturation DO. If DO is greater than or equal to the threshold value T, the process proceeds to step 33, and if it is less than the threshold value T, the present process is terminated.

2. FIG. 8 shows changes in the operating state and changes in DO in the culture apparatus 1 when the culture method of the present embodiment is performed. The state from before sunset to sunrise is the same as in the first embodiment.

After sunrise, DO rises. This is because the photosynthetic microorganism begins to generate oxygen in the culture solution 17 by photosynthesis. When the DO rises after sunrise and exceeds the threshold T, the stop period ends. T ₂ 8 represents the end time of the stop period. After the stop period, since oxygen is taken into the culture solution 17 by the rotation of the stirring paddle 5, DO rises more rapidly and exceeds the saturated DO. After the end of the stop period, the photosynthetic microorganisms and predators are uniformly dispersed in the culture solution 17, and the deposited layer 29 disappears.

3. Effects exhibited by the culture device 1 and the culture method According to the second embodiment described in detail above, the following effects are obtained in addition to the effects of the first embodiment described above.

(2A) culture apparatus 1, together with DO is increasing, the time _{t 2} when DO is equal to or larger than the threshold value T, and ends the stop period. Here, the threshold value T, since the saturated DO value smaller than the time t _2, the DO is the time before the time of reaching the saturation DO. Therefore, the culture apparatus 1 ends the stop period between the time when DO starts to rise and the time when DO reaches saturation DO. Thereby, the proliferation of photosynthetic microorganisms can be promoted. Moreover, it can suppress that a stop period is terminated too early.
<Third Embodiment>
1. Differences from the First Embodiment Since the basic configuration of the third embodiment is the same as that of the first embodiment, the description of the common configurations will be omitted, and differences will be mainly described. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  When performing the culturing method in the third embodiment, the control unit 15 repeatedly performs the process shown in FIG. 9 every predetermined time. Steps 41 to 44 in FIG. 9 are the same as steps 1, 3, 5, and 6 in the first embodiment.

  In step 45, the saturation concentration calculation unit 25 sets a start threshold value. The start threshold value is the same value as the saturated DO calculated in step 44. Note that the start threshold value may be a value larger than the saturation DO or a value smaller than the saturation DO.

  In step 46, the stirring control unit 27 determines whether or not the DO acquired in step 42 is equal to or less than the start threshold value set in step 45. If DO is less than or equal to the start threshold, the process proceeds to step 47, and if DO is greater than the start threshold, this process ends.

In step 47, the stirring control unit 27 starts a stop period.
On the other hand, if a negative determination is made in step 41, the process proceeds to step 48. Steps 48 to 50 are the same as steps 42 to 44 described above.

  In step 51, the saturated concentration calculation unit 25 sets an end threshold value. The end threshold is the same value as the saturated DO calculated in step 50. Note that the end threshold value may be a value larger than the saturation DO or a value smaller than the saturation DO.

  In step 52, the stirring control unit 27 determines whether or not the DO acquired in step 48 is equal to or greater than the end threshold set in step 51. If DO is greater than or equal to the end threshold value, the process proceeds to step 53. If DO is less than the end threshold value, this process ends.

In step 53, the stirring control unit 27 ends the stop period.
3. Effects exhibited by the culture apparatus 1 and the culture method According to the third embodiment described in detail above, in addition to the effects (1A), (1B), (1G), (1H) of the first embodiment described above, the following further An effect is obtained.

(3A) In the culture method of the present embodiment, since it is not necessary to detect sunrise and sunset, the configuration of the culture device 1 and the culture method can be simplified.
(3B) In the culture method of the present embodiment, it is not necessary to determine whether DO is descending or not. Therefore, the culture method can be simplified.
<Other embodiments>
As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the above-mentioned embodiment, It can implement in various deformation | transformation.

(1) The cell concentration OD ₇₂₀ in the culture solution 17 during the stop period can be set as appropriate. FIG. 10 shows the transition of DO when the cell concentration OD ₇₂₀ in the culture solution 17 during the stop period is 0.8. Again, the nighttime DO is sufficiently low.

  (2) Other conditions may be used for starting the suspension period. For example, the stop period may be started when sunset is detected. Further, the stop period may be started when DO becomes equal to or less than a preset start threshold. The start threshold value may be lower than the saturated DO, may be equal to the saturated DO, or higher than the saturated DO. Further, the stop period may be started when a preset start time is reached.

  (3) Other conditions may be used for terminating the suspension period. For example, the stop period may be terminated when sunrise is detected. Further, the stop period may be ended when a preset end time is reached.

(4) The culture apparatus 1 may include a stirring unit other than the stirring paddle 5. For example, the culture solution 17 may be stirred by a method such as vibrating the culture tank 3.
(5) The culture tank 3 may be a tank of a type other than the raceway.

(6) The culture apparatus 1 may not include a culture tank. In this case, the culture apparatus 1 can be assembled to a tank separate from the culture apparatus 1.
(7) The photosynthetic microorganism may be other than Trevoxia algae. For example, photosynthetic microorganisms belonging to the green alga class and the red alga class can be appropriately selected and used.

  (8) The culture apparatus 1 may detect sunrise and sunset by means other than the photon spectrometer 13. For example, the culture apparatus 1 may acquire time and date using a clock, and based on them, may determine whether the current time is before sunrise and whether it is before sunset.

  (9) The functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claim are embodiment of this invention.

  (10) In addition to the culture apparatus described above, a system including the culture apparatus as a constituent element, a program for causing a computer to function as a control unit of the culture apparatus, and a non-transitory actual record such as a semiconductor memory storing the program The present invention can also be realized in various forms such as a medium.

DESCRIPTION OF SYMBOLS 1 ... Culture apparatus, 3 ... Culture tank, 5 ... Stir paddle, 7 ... Drive motor, 9 ... Water thermometer, 9A ... Detection part, 11 ... Dissolved oxygen concentration sensor, 11A ... Detection part, 13 ... Photoquantometer, 15 ... Control 17, culture medium, 19, bottom surface, 21, CPU, 23, memory, 25, saturation concentration calculating unit, 27, stirring control unit, 29, deposited layer

Claims (13)

An agitation unit for agitating the culture solution in a culture tank installed outdoors;
An oxygen concentration detection unit for detecting a dissolved oxygen concentration in the culture solution;
A temperature detection unit for detecting the temperature of the culture solution;
A saturation concentration calculation unit for calculating a saturation concentration of oxygen in the culture solution at a temperature detected by the temperature detection unit;
An agitation control unit that stops the agitation by the agitation unit during at least a part of the stop period of the period in which the dissolved oxygen concentration detected by the oxygen concentration detection unit is equal to or less than the saturation concentration calculated by the saturation concentration calculation unit. When,
An apparatus for culturing photosynthetic microorganisms. A culture apparatus for photosynthetic microorganisms according to claim 1,
The agitation control unit is a culturing apparatus for photosynthetic microorganisms that starts the stop period when the dissolved oxygen concentration detected by the oxygen concentration detection unit decreases from a value equal to or higher than the saturation concentration to the saturation concentration. A photosynthetic microorganism culturing apparatus according to claim 1 or 2,
The stirring control unit, after the start of the stop period, between the time when the dissolved oxygen concentration detected by the oxygen concentration detection unit starts to rise and the time when the dissolved oxygen concentration reaches the saturation concentration, An apparatus for culturing photosynthetic microorganisms that terminates the suspension period. A culture apparatus for photosynthetic microorganisms according to any one of claims 1 to 3,
It has a sunset detection unit that detects sunset,
The agitation control unit is an apparatus for culturing photosynthetic microorganisms that starts the stop period after the sunset detection unit detects sunset. A culture apparatus for photosynthetic microorganisms according to any one of claims 1 to 4,
It has a sunrise detection unit that detects sunrise,
The agitation control unit is a culture apparatus for photosynthetic microorganisms that ends the stop period after the sunrise detection unit detects sunrise. A method for culturing photosynthetic microorganisms that stirs a culture solution in a culture tank installed outdoors,
A method for culturing photosynthetic microorganisms, wherein stirring of the culture solution is stopped during at least a part of the stop period of the period in which the dissolved oxygen concentration in the culture solution is equal to or lower than a saturated concentration. A method for culturing photosynthetic microorganisms according to claim 6,
The method for culturing photosynthetic microorganisms, wherein the suspension period is started when the dissolved oxygen concentration decreases from a value equal to or higher than the saturated concentration to the saturated concentration. A method for culturing photosynthetic microorganisms according to claim 6 or 7,
A method for cultivating photosynthetic microorganisms that ends the suspension period from the time when the dissolved oxygen concentration starts to rise to the time when the dissolved oxygen concentration reaches the saturation concentration after the suspension period starts. A method for culturing photosynthetic microorganisms according to any one of claims 6 to 8,
A method for culturing photosynthetic microorganisms, wherein the suspension period starts after sunset. A method for culturing photosynthetic microorganisms according to any one of claims 6 to 9,
A method for culturing photosynthetic microorganisms, which ends the suspension period after sunrise. A method for culturing photosynthetic microorganisms according to any one of claims 6 to 10,
The method for culturing photosynthetic microorganisms, wherein the cell concentration OD ₇₂₀ in the culture solution is 1.0 or more during the suspension period. A method for culturing photosynthetic microorganisms according to any one of claims 6 to 11,
Measuring the dissolved oxygen concentration and the temperature of the culture in the sedimentary layer containing the photosynthetic microorganisms generated during the suspension period;
A method for culturing photosynthetic microorganisms, wherein the saturation concentration is calculated based on the temperature. A method for culturing photosynthetic microorganisms according to any one of claims 6 to 12,
A method for culturing a photosynthetic microorganism, wherein the photosynthetic microorganism is a green alga class or a Trevoxia algae class.

Images