WO2019198238A1 - Microalga culture method - Google Patents

Microalga culture method Download PDF

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Publication number
WO2019198238A1
WO2019198238A1 PCT/JP2018/015594 JP2018015594W WO2019198238A1 WO 2019198238 A1 WO2019198238 A1 WO 2019198238A1 JP 2018015594 W JP2018015594 W JP 2018015594W WO 2019198238 A1 WO2019198238 A1 WO 2019198238A1
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Prior art keywords
microalgae
growth
liquid medium
adjustment tank
period
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PCT/JP2018/015594
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French (fr)
Japanese (ja)
Inventor
長尾　宣夫
戸田　龍樹
松山　達
モハメド ユソフ，ファティマ
シャリフ モハメド ディン，モハメド
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学校法人 創価大学
ユニバーシティー プトラ マレーシア
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Priority to JP2019560422A priority Critical patent/JP6741284B2/en
Priority to PCT/JP2018/015594 priority patent/WO2019198238A1/en
Publication of WO2019198238A1 publication Critical patent/WO2019198238A1/en

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    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
    • C12N1/12—Unicellular algae; Culture media therefor

Definitions

  • the present invention relates to a method for culturing microalgae.
  • microalgae for absorption of carbon dioxide generated at power plants, factories, etc., domestic wastewater, sewage treatment such as sewage. Since the microalgae have a high growth rate, they are used as raw materials for biofuels, fertilizers, feeds, and the like, as well as high value-added ones used for medicines, nutritional foods, cosmetic raw materials and the like.
  • High-value-added microalgae are vulnerable to contamination and are conventionally cultured in a liquid medium contained in a growth container using a closed growth container configured to be isolated from the outside air.
  • the microalgae fix carbon in the air by photosynthesis and generate oxygen, the oxygen concentration in the growth vessel increases when the growth is active.
  • the microalgae will breathe as a reverse reaction of photosynthesis, and absorb oxygen and release carbon, so the oxygen in the growth vessel is removed. It is preferable to do.
  • a vertical growth vessel is used as the closed growth vessel, and aeration is performed from the bottom of the growth vessel to agitate the liquid medium and simultaneously remove oxygen generated by photosynthesis of the microalgae.
  • the vertical growth vessel has a problem that there is a limit to the number of microalgae that can be cultivated per unit, making it difficult to culture in large quantities.
  • a large number of vertical growth vessels can be used to cultivate microalgae in large quantities.
  • the energy required for stirring, aeration, deaeration, etc. is excessive for the unit weight of the microalgae yield. There is a problem of becoming.
  • the method of culturing microalgae using a horizontal closed growth vessel has the disadvantage that the depth of the liquid medium is limited due to light permeability, and it is difficult to agitate the liquid medium and remove oxygen by aeration.
  • An object of the present invention is to provide a method for culturing microalgae that can eliminate such inconvenience and can stir a liquid medium and remove oxygen even when a horizontal closed growth vessel is used. .
  • the method for culturing microalgae of the present invention comprises the following steps (1) to (4), wherein step (1) is performed during a predetermined growth period, and step (2) ) To step (4), and after performing step (1), at least steps (2) to (4) are performed in a predetermined adjustment period, and the growth period and the adjustment period are repeated.
  • Step (1) Microalgae are placed in a closed growth container configured to be isolated from the outside air, and grown in a photoautotrophic manner in a liquid medium contained in the growth container.
  • Step (2) At least a part or all of the liquid medium on which the microalgae are grown in the step (1) is transferred from the growth vessel to the adjustment tank together with the microalgae.
  • Step (3) The mixture of the microalgae and the liquid medium transferred to the adjustment tank in the step (2) is degassed in the adjustment tank.
  • Step (4) The mixture of the microalgae degassed in the step (3) and the liquid medium is transferred from the adjustment tank to the growth vessel.
  • the microalgae are grown in a photoautotrophic manner in a liquid medium contained in the growth vessel. If it does in this way, in the said growth container, carbon will be fix
  • the microalgae will breathe as a reverse reaction of photosynthesis, and absorb oxygen and release carbon. Therefore, after growing the microalgae as described above, in the step (2) as the adjustment period, at least a part or all of the liquid medium is transferred from the growth vessel to the adjustment tank together with the microalgae. To do.
  • dissolved oxygen in the liquid medium is obtained by degassing the mixture of the microalgae and the liquid medium transferred to the adjustment tank in the adjustment tank in the step (3). Reduce concentration.
  • the step (4) the mixture of the microalgae and the liquid medium whose dissolved oxygen concentration is reduced by the degassing treatment is transferred from the adjustment tank to the growth vessel. And the said process (1) as the said growth period is performed again.
  • the microalgae can be grown in a photoautotrophic manner again in the growth container.
  • the transfer of the mixture of the microalgae and the liquid medium is intermittently repeated between the growth vessel and the adjustment tank, Can be stirred.
  • the liquid medium can be stirred and oxygen can be removed even when a closed growth vessel is used.
  • the method for culturing microalgae of the present invention can be applied even when the growth vessel is a vertical type, but is particularly preferably applied when the growth vessel is a horizontal type container arranged in a horizontal direction. Can do.
  • the transition period from the growth period to the adjustment period may be after the growth period has been performed for a predetermined time, but the liquid medium in which the microalgae are grown It is preferable to determine the concentration based on the dissolved oxygen concentration.
  • the microalgae respirate as a reverse reaction of photosynthesis, and absorb oxygen and release carbon. Therefore, by determining the transition time from the growth period to the adjustment period based on the dissolved oxygen concentration of the liquid medium, it is possible to shift from the growth period to the adjustment period at an appropriate time.
  • the microalgae be grown photoautotrophically by suspending the growth vessel below the surface of water such as lakes and rivers or below the sea level.
  • a large area can be easily secured for installing the growth vessel, while the growth vessel is in water with a large heat capacity, so the microalgae and the liquid medium in the growth vessel It is possible to prevent the temperature of the mixture from rising excessively.
  • the effect that the mixture of the said micro algae in the said growth container and the said liquid culture medium can also be acquired by the wave motion of the water surface or the sea surface.
  • the growth container when the growth container is suspended below the water surface or the sea surface, the growth container has an opening at one end, a part thereof is made of a stretchable material, and the adjustment is performed via a transfer pipe connected to the opening.
  • the mixture is communicated with the tank, and the mixture of the microalgae and the liquid medium is transferred to the adjustment tank by its own weight by allowing the adjustment tank to settle so that the bottom of the adjustment tank is lower than the opening. It is preferable to transfer the mixture of the microalgae and the liquid medium to the growth vessel by its own weight by raising the adjustment tank so that the bottom of the adjustment tank is positioned higher than the opening.
  • the mixture of the microalgae and the liquid medium can be transferred simply by raising and lowering the adjustment tank with respect to the opening, and the energy required for the transfer can be reduced.
  • a space is provided above the liquid medium accommodated in the growth container, and a carrier gas is circulated in the space, so that the microalgae accumulate in the space due to the growth of the microalgae. It is preferable to discharge oxygen.
  • the number of the growth containers may be one, but a plurality may be provided.
  • Explanatory drawing which shows the initial state of transfer in one Embodiment of the cultivation method of the micro algae of this invention.
  • Explanatory drawing which shows the state in the middle of transfer in one Embodiment of the cultivation method of the micro algae of this invention.
  • Explanatory drawing which shows the completion
  • Explanatory drawing which shows other embodiment of the cultivation method of the micro algae of this invention.
  • the method for culturing microalgae of the present invention comprises placing a high-value-added microalgae used in medicines, nutritional foods, cosmetic raw materials, etc. in a closed growth container configured to be isolated from the outside air, Is a culture method for photoautotrophic growth in a liquid medium accommodated in the medium.
  • Examples of the high-value-added microalgae include Haematococcus genus such as Haematococcus pluvialis, Haematococcus lacustris, Chlorella vulgaris, Chlorella sorokiniana, Chlorella ofzofingiensis genus Chlorella, Nannochloropsis Dunaliella genus, Botryococcus braunii, etc., Botryococcus genus such as Botryococcus braunii, other green algae, Isochrysis ⁇ galbana, Isochrysis litoralis etc. , Cyanobacterium including Arthrospira genus such as Arthrospira maxima, Euglena genus such as Euglena gracilis, and the like.
  • the growth vessel may be any material that is made of a light-transmitting material so that the microalgae grow light-autotrophically.
  • a material such as hard polyvinyl chloride, acrylic resin, or glass. What has been configured can be used.
  • the liquid medium those containing nutrients for growing the microalgae photoautotrophically can be used, for example, fresh water medium such as BBM, BG-11, F / 2, Conway, etc.
  • artificial media such as seawater media
  • sewage containing nutrients of microalgae such as nitrogen can be used.
  • the method for culturing microalgae of the present invention can be carried out, for example, by a system using a bag reactor 1 suspended under the water surface S as a growth vessel, as shown in FIG. 1A.
  • the bag reactor 1 is a bag-like container made of a stretchable material such as soft polyvinyl chloride, polyolefin, and fluororesin, and is disposed horizontally in the horizontal direction directly below the water surface S.
  • the bag reactor 1 contains a liquid medium 2 therein, and cultivates microalgae in the liquid medium 2.
  • the bag reactor 1 has an opening at one end, and a transfer pipe 3 is connected to the opening.
  • the other end of the transfer pipe 3 is connected to the bottom of the adjustment tank 4, and as a result, the bag reactor 1 is connected to the adjustment tank 4 via the transfer pipe 3.
  • the adjustment tank 4 includes a cylindrical upper part and a conical bottom part connected to the upper part, and is configured to be able to sink or rise with respect to the water surface S.
  • the microalgae are grown in a photoautotrophic manner in the liquid medium 2 accommodated in the bag reactor 1. This step corresponds to step (1) in the growth period of claim 1.
  • the dissolved oxygen concentration in the liquid medium 2 increases, and when it exceeds the limit, the microalgae breathe as a reverse reaction of photosynthesis and absorb oxygen. Then carbon is released. Therefore, if the dissolved oxygen concentration in the liquid medium 2 exceeds a predetermined range, at least a part or all of the liquid medium 2, for example, 2/3, is mixed with the microalgae as a mixture of the liquid medium 2 and the microalgae. Transfer from the bag reactor 1 to the adjustment tank 4. This step corresponds to step (2) in the adjustment period of claim 1.
  • the microalgae are grown in the bag reactor 1 for a predetermined time.
  • the dissolved oxygen concentration of the liquid medium 2 can be detected, for example, by disposing a water quality sensor equipped with a dissolved oxygen meter or the like in the middle of the transfer tube 3.
  • the water quality sensor may include a pH meter, a turbidity meter, a pressure meter, a salt concentration meter, a thermometer, etc. in addition to the dissolved oxygen meter.
  • the mixture of the liquid medium 2 and the microalgae is transferred from the bag reactor 1 to the adjustment tank 4 by allowing the adjustment tank 4 to settle as shown in FIG. 1B.
  • the adjusting tank 4 is allowed to settle so that the bottom of the adjusting tank 4 is positioned lower than the opening of the bag reactor 1
  • the mixture in the bag reactor 1 enters the adjusting tank 4 through the transfer pipe 3 by its own weight. Be transported.
  • the bag reactor 1 contracts as the mixture is transferred, and can absorb a decrease in volume due to the transfer of the mixture.
  • the transfer of the mixture from the bag reactor 1 to the adjustment tank 4 is completed when most of the mixture in the bag reactor 1 is transferred to the adjustment tank 4 as shown in FIG. 1C.
  • the degassing treatment may be performed by aeration such as aeration in the adjustment tank 4 or may be performed by making the upper space of the mixture in the adjustment tank 4 have a negative pressure. As a result, the dissolved oxygen concentration in the liquid medium 2 can be reduced to the limit, for example.
  • the mixture is then transferred from the adjustment tank 4 to the bag reactor 1. This step corresponds to step (4) in the adjustment period of claim 1.
  • the transfer of the mixture from the adjustment tank 4 to the bag reactor 1 can be performed by raising the adjustment tank 4 from the state shown in FIG. 1C. If it does in this way, the said mixture which becomes a position higher than the opening of the bag reactor 1 in the adjustment tank 4 will be transferred in the bag reactor 1 via the transfer pipe 3 with the dead weight.
  • the transfer pipe 3 is the same as the transfer pipe 3 used when transferring the mixture from the bag reactor 1 to the adjustment tank 4.
  • the mixture is transferred from the adjustment tank 4 to the bag reactor 1 by raising the bottom of the adjustment tank 4 to a position higher than the opening of the bag reactor 1, and most of the mixture in the adjustment tank 4 is transferred to the bag reactor 1. To finish.
  • the microalgae Since the dissolved oxygen is reduced in the liquid medium 2 contained in the mixture transferred to the bag reactor 1, the microalgae starts photoautotrophic growth again.
  • the mixture is transferred from the bag reactor 1 to the adjustment tank 4 and transferred again from the adjustment tank 4 to the bag reactor 1, whereby the liquid medium 2 contained in the mixture is sufficiently stirred, Algae can grow well.
  • the liquid medium 2 can be agitated and oxygen can be removed by repeating the growth period and the adjustment period.
  • the bag reactor 1 is described as being suspended below the water surface S. However, the bag reactor 1 may be suspended below the sea surface. By suspending the bag reactor 1 under the water surface S or the sea surface, a large area can be easily secured for installing the bag reactor 1.
  • the method for culturing microalgae of the present invention can be carried out by a system in which a plurality of bag reactors 1 are arranged on the ground.
  • a bag reactor 1 shown in FIG. 2 is a bag-like container made of the stretchable material, and is disposed horizontally in the horizontal direction on the ground.
  • a plurality of bag reactors 1 are shown to be arranged vertically, but the plurality of bag reactors 1 can be arranged radially around the adjustment tank 4, for example.
  • the size of the bag reactor 1 can be appropriately set according to the volume of the adjustment tank 4, but the depth of the liquid medium 2 accommodated therein is preferably set to 100 mm or less from the light transmittance.
  • Each bag reactor 1 accommodates a liquid medium 2 and is connected to the bottom of the adjustment tank 4 via a transfer pipe 3.
  • the adjustment tank 4 shown in FIG. 2 is hermetically sealed, and the vacuum pump 5 disposed at the top is operated to discharge the internal gas, and the internal pressure is reduced to at least a part of the liquid medium 2 or All, for example, 2/3 can be transferred from the bag reactor 1 to the adjusting tank 4 as a mixture of the liquid culture medium 2 and the microalgae together with the microalgae.
  • the mixture is degassed by aeration by aeration or the like, or by making the upper space of the mixture in the adjustment tank 4 have a negative pressure.
  • carbon dioxide may be added to the mixture as a carbon source, and the amount of carbon dioxide added is a water quality sensor disposed in the middle of the transfer pipe 3, and the mixture detected by the water quality sensor. It can be determined based on the carbon dioxide concentration in the medium.
  • the temperature of the mixture may be adjusted by a charging temperature controller.
  • the bottom of the adjustment tank 4 is positioned higher than each bag reactor 1.
  • the operation of the vacuum pump 5 is stopped and the outside air is introduced into the adjustment tank 4, whereby the mixture in the adjustment tank 4 is transferred to the bag reactor 1 through the transfer pipe 3 by its own weight. Can be transported.
  • the transfer pipe 3 is the same as the transfer pipe 3 used when transferring the mixture from the bag reactor 1 to the adjustment tank 4.
  • the microalgae can be cultured in the same manner as the system shown in FIG. 1, and the liquid medium 2 is stirred by repeating the growth period and the adjustment period. And oxygen can be removed.
  • a space 6 is provided above the liquid culture medium 2 in the bag reactor 1, a gas introduction pipe 7 a that introduces air as a carrier gas into the space 6, and a gas that discharges the carrier gas from the space 6.
  • a discharge pipe 7b can also be provided.
  • the dissolved oxygen concentration in the liquid medium 2 can be reduced in the bag reactor 1 during the growth period, and the growth period can be further increased, while the mixture from the bag reactor 1 to the adjustment tank 4 is increased.
  • the number of times of transfer can be reduced.
  • the bag reactor 1 is a horizontal growth container arranged in the horizontal direction.
  • the bag reactor 1 may be a vertical growth container arranged in the vertical direction. Good.
  • 1 bag reactor (growth vessel), 2 ... liquid medium, 4 ... regulation tank.

Abstract

Provided is a microalga culture method with which even when a horizontal, closed growth container is used, a liquid medium can be stirred and oxygen can be removed therefrom. During a growth period, a microalga is photoautotrophically cultivated in a liquid medium 2 contained in a closed bag reactor 1. In an adjustment period, the liquid medium 2 in which the microalga has grown is transferred from the bag reactor 1 to an adjustment tank 4 with the microalga therein, is subjected to a degas treatment in the adjustment tank 4, and then is transferred from the adjustment tank 4 to the bag reactor 1. The growth period and the adjustment period are repeated.

Description

微細藻類の培養方法Microalgae culture method
　本発明は、微細藻類の培養方法に関する。 The present invention relates to a method for culturing microalgae.
　近年、発電所、工場等で発生する二酸化炭素の吸収、生活排水、下水等の汚水処理等のために微細藻類を培養することが検討されている。前記微細藻類は増殖速度が速いため、バイオ燃料、肥料、飼料等の原料に用いられる他、薬品、栄養食品、化粧品原料等に用いられる付加価値の高いものも知られている。 In recent years, it has been studied to culture microalgae for absorption of carbon dioxide generated at power plants, factories, etc., domestic wastewater, sewage treatment such as sewage. Since the microalgae have a high growth rate, they are used as raw materials for biofuels, fertilizers, feeds, and the like, as well as high value-added ones used for medicines, nutritional foods, cosmetic raw materials and the like.
　付加価値の高い微細藻類は汚染に弱く、従来、外気から隔離されるように構成された閉鎖式の生育容器を用い、該生育容器に収容された液体培地中で培養されている。 High-value-added microalgae are vulnerable to contamination and are conventionally cultured in a liquid medium contained in a growth container using a closed growth container configured to be isolated from the outside air.
　前記閉鎖式の生育容器を用いて前記微細藻類を培養する場合、該微細藻類を効率良く増殖させるためには、前記液体培地を撹拌する必要がある。一方、前記微細藻類は光合成により空中の炭素を固定し、酸素を発生するので、増殖が盛んになると前記生育容器内の酸素濃度が高くなる。前記微細藻類は、前記生育容器内の酸素濃度が高くなると、光合成の逆反応として呼吸を行うようになり、酸素を吸収して炭素を放出するようになるので、該生育容器内の酸素を除去することが好ましい。 When culturing the microalgae using the closed growth vessel, it is necessary to agitate the liquid medium in order to efficiently proliferate the microalgae. On the other hand, since the microalgae fix carbon in the air by photosynthesis and generate oxygen, the oxygen concentration in the growth vessel increases when the growth is active. When the oxygen concentration in the growth vessel becomes high, the microalgae will breathe as a reverse reaction of photosynthesis, and absorb oxygen and release carbon, so the oxygen in the growth vessel is removed. It is preferable to do.
　そこで、前記閉鎖式の生育容器として、縦型の生育容器を用い、該生育容器の底部からエアレーションを行うことにより、前記液体培地を撹拌すると同時に前記微細藻類の光合成により発生する酸素を除去することが行われている。ところが、縦型の生育容器は、１基当たりで培養できる微細藻類に限度があり、大量に培養することが難しいという問題がある。多数の縦型の生育容器を用いれば微細藻類を大量に培養することはできるが、この場合には、微細藻類の収量の単位重量当たりに対し、撹拌、曝気、脱気等に要するエネルギーが過大になるという問題がある。 Therefore, a vertical growth vessel is used as the closed growth vessel, and aeration is performed from the bottom of the growth vessel to agitate the liquid medium and simultaneously remove oxygen generated by photosynthesis of the microalgae. Has been done. However, the vertical growth vessel has a problem that there is a limit to the number of microalgae that can be cultivated per unit, making it difficult to culture in large quantities. A large number of vertical growth vessels can be used to cultivate microalgae in large quantities. However, in this case, the energy required for stirring, aeration, deaeration, etc. is excessive for the unit weight of the microalgae yield. There is a problem of becoming.
　前記問題を解決するために、より少ないエネルギーで微細藻類を大量に培養することができる横型の閉鎖式の生育容器を用いることが検討されている（例えば、特許文献１参照）。 In order to solve the above problem, it has been studied to use a horizontal closed growth vessel capable of culturing a large amount of microalgae with less energy (for example, see Patent Document 1).
特開平８－１７３１３９号公報JP-A-8-173139
　しかしながら、横型の閉鎖式の生育容器を用いる微細藻類の培養方法では、光の透過性から液体培地の深さに制限があり、エアレーションによる液体培地の撹拌及び酸素の除去が難しいという不都合がある。 However, the method of culturing microalgae using a horizontal closed growth vessel has the disadvantage that the depth of the liquid medium is limited due to light permeability, and it is difficult to agitate the liquid medium and remove oxygen by aeration.
　本発明は、かかる不都合を解消して、横型の閉鎖式の生育容器を用いる場合にも、液体培地の撹拌及び酸素の除去を行うことができる微細藻類の培養方法を提供することを目的とする。 An object of the present invention is to provide a method for culturing microalgae that can eliminate such inconvenience and can stir a liquid medium and remove oxygen even when a horizontal closed growth vessel is used. .
　かかる目的を達成するために、本発明の微細藻類の培養方法は、下記の工程（１）～工程（４）を備え、所定の生育期間には工程（１）を行い、且つ、工程（２）～工程（４）は行なわず、工程（１）を行った後に所定の調整期間には少なくとも工程（２）～工程（４）を行い、前記生育期間と前記調整期間とを繰り返すことを特徴とする。
工程（１）：微細藻類を外気から隔離されるように構成された閉鎖式の生育容器に入れ、該生育容器に収容された液体培地中で光独立栄養的に生育させる。
工程（２）：前記工程（１）において前記微細藻類を生育させた前記液体培地の少なくとも一部又は全部を該微細藻類ごと前記生育容器から調整槽に移送する。
工程（３）：前記工程（２）において前記調整槽に移送した前記微細藻類及び前記液体培地の混合物を該調整槽内で脱ガス処理する。
工程（４）：前記工程（３）において脱ガス処理した前記微細藻類及び前記液体培地の混合物を前記調整槽から前記生育容器に移送する。 In order to achieve this object, the method for culturing microalgae of the present invention comprises the following steps (1) to (4), wherein step (1) is performed during a predetermined growth period, and step (2) ) To step (4), and after performing step (1), at least steps (2) to (4) are performed in a predetermined adjustment period, and the growth period and the adjustment period are repeated. And
Step (1): Microalgae are placed in a closed growth container configured to be isolated from the outside air, and grown in a photoautotrophic manner in a liquid medium contained in the growth container.
Step (2): At least a part or all of the liquid medium on which the microalgae are grown in the step (1) is transferred from the growth vessel to the adjustment tank together with the microalgae.
Step (3): The mixture of the microalgae and the liquid medium transferred to the adjustment tank in the step (2) is degassed in the adjustment tank.
Step (4): The mixture of the microalgae degassed in the step (3) and the liquid medium is transferred from the adjustment tank to the growth vessel.
　本発明の微細藻類の培養方法では、まず、前記生育期間としての前記工程（１）で、前記生育容器に収容された液体培地中で前記微細藻類を光独立栄養的に生育させる。このようにすると、前記生育容器内では前記微細藻類の光独立栄養的生育（光合成）により炭素が固定されると同時に酸素が発生し、該酸素は前記液体培地中に溶存している。 In the method for culturing microalgae of the present invention, first, in the step (1) as the growth period, the microalgae are grown in a photoautotrophic manner in a liquid medium contained in the growth vessel. If it does in this way, in the said growth container, carbon will be fix | immobilized simultaneously with the photoautotrophic growth (photosynthesis) of the said micro algae, and oxygen will be generated, and this oxygen is dissolved in the said liquid culture medium.
　このとき、前記液体培地中の溶存酸素濃度が限度を超えて高くなると、前記微細藻類は光合成の逆反応として呼吸を行うようになり、酸素を吸収して炭素を放出するようになる。そこで、前述のように前記微細藻類を生育させた後、前記調整期間としての前記工程（２）で、前記液体培地の少なくとも一部又は全部を該微細藻類ごと該生育容器から前記調整槽に移送する。 At this time, if the dissolved oxygen concentration in the liquid medium becomes higher than the limit, the microalgae will breathe as a reverse reaction of photosynthesis, and absorb oxygen and release carbon. Therefore, after growing the microalgae as described above, in the step (2) as the adjustment period, at least a part or all of the liquid medium is transferred from the growth vessel to the adjustment tank together with the microalgae. To do.
　前記調整期間では、次いで、前記工程（３）で、前記調整槽に移送された前記微細藻類及び前記液体培地の混合物を、該調整槽内で脱ガス処理することにより該液体培地中の溶存酸素濃度を低下させる。そして、前記工程（４）で、前記微細藻類と、前記脱ガス処理により溶存酸素濃度が低下した前記液体培地との混合物を前記調整槽から前記生育容器に移送する。そして、再び前記生育期間としての前記工程（１）を行う。 Next, in the adjustment period, dissolved oxygen in the liquid medium is obtained by degassing the mixture of the microalgae and the liquid medium transferred to the adjustment tank in the adjustment tank in the step (3). Reduce concentration. Then, in the step (4), the mixture of the microalgae and the liquid medium whose dissolved oxygen concentration is reduced by the degassing treatment is transferred from the adjustment tank to the growth vessel. And the said process (1) as the said growth period is performed again.
　この結果、前記調整期間後の前記生育期間において、前記生育容器内では再び前記微細藻類を光独立栄養的に生育させることができる。 As a result, in the growth period after the adjustment period, the microalgae can be grown in a photoautotrophic manner again in the growth container.
　また、前記生育期間と前記調整期間とを繰り返すことにより、前記生育容器と前記調整槽との間で前記微細藻類及び前記液体培地の混合物の移送が間欠的に繰り返されることとなり、該液体培地を撹拌することができる。 Further, by repeating the growth period and the adjustment period, the transfer of the mixture of the microalgae and the liquid medium is intermittently repeated between the growth vessel and the adjustment tank, Can be stirred.
　従って、本発明の微細藻類の培養方法によれば、閉鎖式の生育容器を用いる場合にも、前記液体培地の撹拌及び酸素の除去を行うことができる。 Therefore, according to the method for culturing microalgae of the present invention, the liquid medium can be stirred and oxygen can be removed even when a closed growth vessel is used.
　本発明の微細藻類の培養方法は、前記生育容器が縦型である場合にも適用することができるが、該生育容器が水平方向に配置される横型の容器である場合に特に好ましく適用することができる。 The method for culturing microalgae of the present invention can be applied even when the growth vessel is a vertical type, but is particularly preferably applied when the growth vessel is a horizontal type container arranged in a horizontal direction. Can do.
　また、本発明の微細藻類の培養方法において、前記生育期間から前記調整期間への移行時期は、該生育期間を所定時間行った後としてもよいが、前記微細藻類を生育させている前記液体培地の溶存酸素濃度に基づいて決定することが好ましい。 In the method for culturing microalgae of the present invention, the transition period from the growth period to the adjustment period may be after the growth period has been performed for a predetermined time, but the liquid medium in which the microalgae are grown It is preferable to determine the concentration based on the dissolved oxygen concentration.
　前述のように、前記液体培地中の溶存酸素濃度が限度を超えて高くなると、前記微細藻類は光合成の逆反応として呼吸を行うようになり、酸素を吸収して炭素を放出するようになる。従って、前記液体培地の溶存酸素濃度に基づいて、前記生育期間から前記調整期間への移行時期を決定することにより、適切な時期に該生育期間から該調整期間へ移行することができる。 As described above, when the dissolved oxygen concentration in the liquid medium becomes higher than the limit, the microalgae respirate as a reverse reaction of photosynthesis, and absorb oxygen and release carbon. Therefore, by determining the transition time from the growth period to the adjustment period based on the dissolved oxygen concentration of the liquid medium, it is possible to shift from the growth period to the adjustment period at an appropriate time.
　また、本発明の微細藻類の培養方法では、前記生育容器を湖沼、河川等の水面下又は海面下に浮遊させて、前記微細藻類を光独立栄養的に生育させることが好ましい。このようにするときには、前記生育容器を設置するために広い面積を容易に確保することができる一方、該生育容器が熱容量の大きな水中にあるため、該生育容器内の前記微細藻類及び前記液体培地の混合物の温度が過度に上昇することを防止することができる。また、水面又は海面の波動により、前記生育容器内の前記微細藻類及び前記液体培地の混合物を混合するという効果も得ることができる。 Moreover, in the method for culturing microalgae of the present invention, it is preferable that the microalgae be grown photoautotrophically by suspending the growth vessel below the surface of water such as lakes and rivers or below the sea level. When doing so, a large area can be easily secured for installing the growth vessel, while the growth vessel is in water with a large heat capacity, so the microalgae and the liquid medium in the growth vessel It is possible to prevent the temperature of the mixture from rising excessively. Moreover, the effect that the mixture of the said micro algae in the said growth container and the said liquid culture medium can also be acquired by the wave motion of the water surface or the sea surface.
　また、前記生育容器を水面下又は海面下に浮遊させるときには、前記生育容器は、一端に開口を有し、一部が伸縮性素材からなり、該開口に接続された移送管を介して前記調整槽に連通しており、該調整槽を該調整槽の底が該開口より低い位置になるように沈降させることにより、前記微細藻類及び前記液体培地の混合物を自重により前記調整槽に移送し、該調整槽を該調整槽の底が該開口より高い位置になるように上昇させることにより、前記微細藻類及び前記液体培地の混合物を自重により前記生育容器に移送することが好ましい。 Further, when the growth container is suspended below the water surface or the sea surface, the growth container has an opening at one end, a part thereof is made of a stretchable material, and the adjustment is performed via a transfer pipe connected to the opening. The mixture is communicated with the tank, and the mixture of the microalgae and the liquid medium is transferred to the adjustment tank by its own weight by allowing the adjustment tank to settle so that the bottom of the adjustment tank is lower than the opening. It is preferable to transfer the mixture of the microalgae and the liquid medium to the growth vessel by its own weight by raising the adjustment tank so that the bottom of the adjustment tank is positioned higher than the opening.
　このようにするときには、前記調整槽を前記開口に対して昇降させるだけで、前記微細藻類及び前記液体培地の混合物の移送を行うことができ、該移送に要するエネルギーを低減することができる。 In doing so, the mixture of the microalgae and the liquid medium can be transferred simply by raising and lowering the adjustment tank with respect to the opening, and the energy required for the transfer can be reduced.
　また、本発明の微細藻類の培養方法では、前記生育容器に収容された前記液体培地の上方に空間を設け、該空間にキャリア気体を流通させて、前記微細藻類の生育により該空間内に溜まった酸素を排出することが好ましい。 Further, in the method for culturing microalgae of the present invention, a space is provided above the liquid medium accommodated in the growth container, and a carrier gas is circulated in the space, so that the microalgae accumulate in the space due to the growth of the microalgae. It is preferable to discharge oxygen.
　このようにするときには、前記微細藻類の生育により前記液体培地の上方の空間に酸素が溜まるが、該酸素を前記キャリア気体により排出することができるので、前記生育期間をより長くすることができ、前記生育容器から前記調整槽への前記微細藻類及び前記液体培地の混合物の移送回数を低減することができる。 When doing so, oxygen accumulates in the space above the liquid medium due to the growth of the microalgae, but since the oxygen can be discharged by the carrier gas, the growth period can be longer, The number of transfers of the mixture of the microalgae and the liquid medium from the growth vessel to the adjustment tank can be reduced.
　また、本発明の微細藻類の培養方法では、前記生育容器は１つでもよいが、複数設けるようにしてもよい。 Moreover, in the method for culturing microalgae of the present invention, the number of the growth containers may be one, but a plurality may be provided.
本発明の微細藻類の培養方法の一実施形態において、移送の初期状態を示す説明図。Explanatory drawing which shows the initial state of transfer in one Embodiment of the cultivation method of the micro algae of this invention. 本発明の微細藻類の培養方法の一実施形態において、移送の途中の状態を示す説明図。Explanatory drawing which shows the state in the middle of transfer in one Embodiment of the cultivation method of the micro algae of this invention. 本発明の微細藻類の培養方法の一実施形態において、移送の終了状態を示す説明図。Explanatory drawing which shows the completion | finish state of transfer in one Embodiment of the cultivation method of the micro algae of this invention. 本発明の微細藻類の培養方法の他の実施形態を示す説明図。Explanatory drawing which shows other embodiment of the cultivation method of the micro algae of this invention.
　次に、添付の図面を参照しながら本発明の実施の形態についてさらに詳しく説明する。 Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
　本発明の微細藻類の培養方法は、薬品、栄養食品、化粧品原料等に用いられる付加価値の高い微細藻類を、外気から隔離されるように構成された閉鎖式の生育容器に入れ、該生育容器に収容された液体培地中で光独立栄養的に生育させる培養方法である。前記付加価値の高い微細藻類としては、例えば、Haematococcus pluvialis, Haematococcus lacustris等のHaematococcus属、 Chlorella vulgaris, Chlorella sorokiniana, Chlorella zofingiensis等のChlorella属、Nannochloropsis oculate等のNannochloropsis属、Dunaliella salina, Dunaliella bardawil, Dunaliella tertiolecta等のDunaliella属、Botryococcus braunii等のBotryococcus属、その他の緑藻類、Isochrysis galbana, Isochrysis litoralis等のIsochrysis属をはじめとするハプト藻類、 Chaetoceros gracilis, Chaetoceros calcitrans等のChaetoceros属をはじめとする珪藻類、 Arthrospira platensis, Arthrospira maxima等のArthrospira属をはじめとするラン藻類、Euglena gracilis等のEuglena属等を挙げることができる。 The method for culturing microalgae of the present invention comprises placing a high-value-added microalgae used in medicines, nutritional foods, cosmetic raw materials, etc. in a closed growth container configured to be isolated from the outside air, Is a culture method for photoautotrophic growth in a liquid medium accommodated in the medium. Examples of the high-value-added microalgae include Haematococcus genus such as Haematococcus pluvialis, Haematococcus lacustris, Chlorella vulgaris, Chlorella sorokiniana, Chlorella ofzofingiensis genus Chlorella, Nannochloropsis Dunaliella genus, Botryococcus braunii, etc., Botryococcus genus such as Botryococcus braunii, other green algae, Isochrysis ハ galbana, Isochrysis litoralis etc. , Cyanobacterium including Arthrospira genus such as Arthrospira maxima, Euglena genus such as Euglena gracilis, and the like.
　前記生育容器としては、前記微細藻類が光独立栄養的に生育するために、光透過性素材により構成されているものであればよく、例えば、硬質ポリ塩化ビニル、アクリル樹脂、ガラス等の素材から構成されているものを用いることができる。また、前記液体培地としては、前記微細藻類が光独立栄養的に生育するための養分を含むものを用いることができ、例えば、BBM、BG-11などの淡水培地、F/2、Conwayなどの海水培地等の人工培地の他、窒素等の微細藻類の栄養を含む汚水等を挙げることができる。 The growth vessel may be any material that is made of a light-transmitting material so that the microalgae grow light-autotrophically. For example, from a material such as hard polyvinyl chloride, acrylic resin, or glass. What has been configured can be used. Further, as the liquid medium, those containing nutrients for growing the microalgae photoautotrophically can be used, for example, fresh water medium such as BBM, BG-11, F / 2, Conway, etc. In addition to artificial media such as seawater media, sewage containing nutrients of microalgae such as nitrogen can be used.
　本発明の微細藻類の培養方法は、例えば、図１Ａに示すように、水面Ｓ下に浮遊させたバッグリアクター１を生育容器とするシステムにより実施することができる。バッグリアクター１は、軟質ポリ塩化ビニル、ポリオレフィン、フッ素樹脂等の伸縮性素材からなる袋状の容器であり、水面Ｓの直下に水平方向に横型に配置される。バッグリアクター１は、内部に液体培地２が収容されており、液体培地２中で、微細藻類の培養を行う。 The method for culturing microalgae of the present invention can be carried out, for example, by a system using a bag reactor 1 suspended under the water surface S as a growth vessel, as shown in FIG. 1A. The bag reactor 1 is a bag-like container made of a stretchable material such as soft polyvinyl chloride, polyolefin, and fluororesin, and is disposed horizontally in the horizontal direction directly below the water surface S. The bag reactor 1 contains a liquid medium 2 therein, and cultivates microalgae in the liquid medium 2.
　また、バッグリアクター１は、一端に開口を有し、該開口に移送管３が接続されている。移送管３の他端は調整槽４の底部に接続されており、この結果、バッグリアクター１は、移送管３を介して調整槽４に接続されている。調整槽４は、円筒状の上部と、該上部に連接する円錐状の底部とからなり、水面Ｓに対して沈降又は上昇自在に構成されている。 Moreover, the bag reactor 1 has an opening at one end, and a transfer pipe 3 is connected to the opening. The other end of the transfer pipe 3 is connected to the bottom of the adjustment tank 4, and as a result, the bag reactor 1 is connected to the adjustment tank 4 via the transfer pipe 3. The adjustment tank 4 includes a cylindrical upper part and a conical bottom part connected to the upper part, and is configured to be able to sink or rise with respect to the water surface S.
　図１Ａに示すシステムでは、まず、バッグリアクター１内に収容された液体培地２中で前記微細藻類を光独立栄養的に生育させる。この工程が請求項１の生育期間における工程（１）に当たる。 In the system shown in FIG. 1A, first, the microalgae are grown in a photoautotrophic manner in the liquid medium 2 accommodated in the bag reactor 1. This step corresponds to step (1) in the growth period of claim 1.
　前述のようにして前記微細藻類を生育させると、該微細藻類の光合成により、液体培地２中の二酸化炭素等の炭素が固定される一方、酸素が発生し、該酸素は液体培地２中に蓄積される。このとき、バッグリアクター１は熱容量の大きな真水中にあるため、バッグリアクター１内の前記微細藻類及び液体培地２の混合物の温度が過度に上昇することを防止することができ、例えば気温が３０℃以上になるような地域又は季節での使用に有利である。 When the microalgae are grown as described above, carbon such as carbon dioxide in the liquid medium 2 is fixed by photosynthesis of the microalgae, while oxygen is generated and the oxygen is accumulated in the liquid medium 2. Is done. At this time, since the bag reactor 1 is in fresh water having a large heat capacity, the temperature of the mixture of the microalgae and the liquid medium 2 in the bag reactor 1 can be prevented from rising excessively. It is advantageous for use in the region or season as described above.
　バッグリアクター１内では前記微細藻類が生育するに従って液体培地２中の溶存酸素濃度が上昇し、限度を超えて高くなると、前記微細藻類は光合成の逆反応として呼吸を行うようになり、酸素を吸収して炭素を放出するようになる。そこで、液体培地２中の溶存酸素濃度が所定の範囲を超えたならば、液体培地２の少なくとも一部又は全部、例えば２／３を前記微細藻類ごと、液体培地２及び微細藻類の混合物として、バッグリアクター１から調整槽４に移送する。この工程が請求項１の調整期間における工程（２）に当たる。 In the bag reactor 1, as the microalgae grow, the dissolved oxygen concentration in the liquid medium 2 increases, and when it exceeds the limit, the microalgae breathe as a reverse reaction of photosynthesis and absorb oxygen. Then carbon is released. Therefore, if the dissolved oxygen concentration in the liquid medium 2 exceeds a predetermined range, at least a part or all of the liquid medium 2, for example, 2/3, is mixed with the microalgae as a mixture of the liquid medium 2 and the microalgae. Transfer from the bag reactor 1 to the adjustment tank 4. This step corresponds to step (2) in the adjustment period of claim 1.
　液体培地２及び微細藻類の混合物を、バッグリアクター１から調整槽４に移送する時期、換言すれば、前記生育期間から前記調整期間への移行時期は、バッグリアクター１において前記微細藻類を所定時間生育させた後としてもよいが、液体培地２の溶存酸素濃度に基づいて決定することが好ましく、より適切な時期を選択することができる。 When the mixture of the liquid medium 2 and the microalgae is transferred from the bag reactor 1 to the adjustment tank 4, in other words, when the growth period is shifted to the adjustment period, the microalgae are grown in the bag reactor 1 for a predetermined time. However, it is preferable to make a determination based on the dissolved oxygen concentration of the liquid medium 2, and a more appropriate time can be selected.
　液体培地２の溶存酸素濃度は、例えば、移送管３の途中に溶存酸素計等を備える水質センサを配設することにより検知することができる。前記水質センサは、溶存酸素計の他、ｐＨメーター、濁度計、圧力計、塩濃度計、温度計等を備えていてもよい。 The dissolved oxygen concentration of the liquid medium 2 can be detected, for example, by disposing a water quality sensor equipped with a dissolved oxygen meter or the like in the middle of the transfer tube 3. The water quality sensor may include a pH meter, a turbidity meter, a pressure meter, a salt concentration meter, a thermometer, etc. in addition to the dissolved oxygen meter.
　図１Ａに示すシステムでは、液体培地２及び微細藻類の混合物のバッグリアクター１から調整槽４への移送を、図１Ｂに示すように、調整槽４を沈降させることにより行う。調整槽４を沈降させ、調整槽４の底がバッグリアクター１の開口より低い位置になるようにすると、バッグリアクター１内の前記混合物が、その自重により移送管３を介して調整槽４内に移送される。このとき、バッグリアクター１はその一部が前記伸縮性素材からなるので、前記混合物が移送されるに従って収縮し、該混合物の移送による容積の減少を吸収することができる。 In the system shown in FIG. 1A, the mixture of the liquid medium 2 and the microalgae is transferred from the bag reactor 1 to the adjustment tank 4 by allowing the adjustment tank 4 to settle as shown in FIG. 1B. When the adjusting tank 4 is allowed to settle so that the bottom of the adjusting tank 4 is positioned lower than the opening of the bag reactor 1, the mixture in the bag reactor 1 enters the adjusting tank 4 through the transfer pipe 3 by its own weight. Be transported. At this time, since part of the bag reactor 1 is made of the stretchable material, the bag reactor 1 contracts as the mixture is transferred, and can absorb a decrease in volume due to the transfer of the mixture.
　前記混合物のバッグリアクター１から調整槽４への移送は、図１Ｃに示すように、バッグリアクター１内の該混合物の大部分が調整槽４に移送されることにより終了する。 The transfer of the mixture from the bag reactor 1 to the adjustment tank 4 is completed when most of the mixture in the bag reactor 1 is transferred to the adjustment tank 4 as shown in FIG. 1C.
　前記混合物の大部分が調整槽４に移送されたならば、次いで、該混合物を調整槽４内で脱ガス処理する。この工程が請求項１の調整期間における工程（３）に当たる。 When most of the mixture has been transferred to the adjustment tank 4, the mixture is then degassed in the adjustment tank 4. This step corresponds to step (3) in the adjustment period of claim 1.
　前記脱ガス処理は、調整槽４内でエアレーション等による曝気により行ってもよく、調整槽４内で前記混合物の上部空間を負圧にすることより行ってもよい。この結果、液体培地２中の溶存酸素濃度を、例えば極限まで低減させることができる。 The degassing treatment may be performed by aeration such as aeration in the adjustment tank 4 or may be performed by making the upper space of the mixture in the adjustment tank 4 have a negative pressure. As a result, the dissolved oxygen concentration in the liquid medium 2 can be reduced to the limit, for example.
　前記脱ガス処理により液体培地２中の溶存酸素濃度が低減されたならば、次に、前記混合物を、調整槽４からバッグリアクター１に移送する。この工程が請求項１の調整期間における工程（４）に当たる。 If the dissolved oxygen concentration in the liquid medium 2 is reduced by the degassing process, the mixture is then transferred from the adjustment tank 4 to the bag reactor 1. This step corresponds to step (4) in the adjustment period of claim 1.
　前記混合物の調整槽４からバッグリアクター１への移送は、図１Ｃに示す状態から調整槽４を上昇させることにより行うことができる。このようにすると、調整槽４内でバッグリアクター１の開口より高い位置になる前記混合物が、その自重により、移送管３を介してバッグリアクター１内に移送される。移送管３は、前記混合物をバッグリアクター１から調整槽４へ移送する際に用いた移送管３と同一である。前記混合物の調整槽４からバッグリアクター１への移送は、調整槽４の底がバッグリアクター１の開口より高い位置まで上昇され、調整槽４の該混合物の大部分がバッグリアクター１に移送されることにより終了する。 The transfer of the mixture from the adjustment tank 4 to the bag reactor 1 can be performed by raising the adjustment tank 4 from the state shown in FIG. 1C. If it does in this way, the said mixture which becomes a position higher than the opening of the bag reactor 1 in the adjustment tank 4 will be transferred in the bag reactor 1 via the transfer pipe 3 with the dead weight. The transfer pipe 3 is the same as the transfer pipe 3 used when transferring the mixture from the bag reactor 1 to the adjustment tank 4. The mixture is transferred from the adjustment tank 4 to the bag reactor 1 by raising the bottom of the adjustment tank 4 to a position higher than the opening of the bag reactor 1, and most of the mixture in the adjustment tank 4 is transferred to the bag reactor 1. To finish.
　バッグリアクター１に移送された前記混合物に含まれる液体培地２は溶存酸素が低減されているので、前記微細藻類は再び光独立栄養的生育を開始する。また、前記混合物がバッグリアクター１から調整槽４へ移送され、調整槽４から再びバッグリアクター１へ移送されることにより、該混合物に含まれる液体培地２が十分に撹拌されることとなり、前記微細藻類を良好に生育させることができる。 Since the dissolved oxygen is reduced in the liquid medium 2 contained in the mixture transferred to the bag reactor 1, the microalgae starts photoautotrophic growth again. In addition, the mixture is transferred from the bag reactor 1 to the adjustment tank 4 and transferred again from the adjustment tank 4 to the bag reactor 1, whereby the liquid medium 2 contained in the mixture is sufficiently stirred, Algae can grow well.
　従って、図１Ａに示すシステムでは、前記生育期間と前記調整期間とを繰り返すことにより、液体培地２の撹拌及び酸素の除去を行うことができる。 Therefore, in the system shown in FIG. 1A, the liquid medium 2 can be agitated and oxygen can be removed by repeating the growth period and the adjustment period.
　尚、図１Ａでは、バッグリアクター１を水面Ｓ下に浮遊させるものとして説明しているが、バッグリアクター１は海面下に浮遊させるようにしてもよい。バッグリアクター１を水面Ｓ下又は海面下に浮遊させることにより、バッグリアクター１を設置するために広い面積を容易に確保することができる。 In FIG. 1A, the bag reactor 1 is described as being suspended below the water surface S. However, the bag reactor 1 may be suspended below the sea surface. By suspending the bag reactor 1 under the water surface S or the sea surface, a large area can be easily secured for installing the bag reactor 1.
　また、本発明の微細藻類の培養方法は、図２に示すように、複数のバッグリアクター１を地上に配置するシステムにより実施することもできる。図２に示すバッグリアクター１は、前記伸縮性素材からなる袋状の容器であり、地上に水平方向に横型に配置される。図２では便宜的に複数のバッグリアクター１を垂直に配置するように示しているが、複数のバッグリアクター１は例えば調整槽４の周囲に放射状に配置することができる。 Moreover, as shown in FIG. 2, the method for culturing microalgae of the present invention can be carried out by a system in which a plurality of bag reactors 1 are arranged on the ground. A bag reactor 1 shown in FIG. 2 is a bag-like container made of the stretchable material, and is disposed horizontally in the horizontal direction on the ground. In FIG. 2, for convenience, a plurality of bag reactors 1 are shown to be arranged vertically, but the plurality of bag reactors 1 can be arranged radially around the adjustment tank 4, for example.
　バッグリアクター１の大きさは調整槽４の容積に対応して適宜設定することができるが、内部に収容される液体培地２の深さは光の透過性から１００ｍｍ以下とすることが好ましい。 The size of the bag reactor 1 can be appropriately set according to the volume of the adjustment tank 4, but the depth of the liquid medium 2 accommodated therein is preferably set to 100 mm or less from the light transmittance.
　各バッグリアクター１は、液体培地２を収容しており、移送管３を介して調整槽４の底部に接続されている。図２に示す調整槽４は密閉されており、上部に配設された真空ポンプ５を作動させて内部の気体を排出し、内部を負圧にすることにより、液体培地２の少なくとも一部又は全部、例えば２／３を前記微細藻類ごと、液体培地２及び微細藻類の混合物として、バッグリアクター１から調整槽４に移送することができる。 Each bag reactor 1 accommodates a liquid medium 2 and is connected to the bottom of the adjustment tank 4 via a transfer pipe 3. The adjustment tank 4 shown in FIG. 2 is hermetically sealed, and the vacuum pump 5 disposed at the top is operated to discharge the internal gas, and the internal pressure is reduced to at least a part of the liquid medium 2 or All, for example, 2/3 can be transferred from the bag reactor 1 to the adjusting tank 4 as a mixture of the liquid culture medium 2 and the microalgae together with the microalgae.
　調整槽４では、エアレーション等による曝気を行うか、調整槽４内で前記混合物の上部空間を負圧にすることより、前記混合物の脱ガス処理を行う。また、調整槽４では、前記混合物に炭素源として二酸化炭素を添加してもよく、二酸化炭素の添加量は移送管３の途中に水質センサを配設し、該水質センサにより検知される該混合物中の二酸化炭素濃度に基づいて決定することができる。さらに、調整槽４では、前記水質センサにより検知される前記混合物の温度に基づき、投入式温調器により該混合物の温度調整を行ってもよい。 In the adjustment tank 4, the mixture is degassed by aeration by aeration or the like, or by making the upper space of the mixture in the adjustment tank 4 have a negative pressure. Further, in the adjustment tank 4, carbon dioxide may be added to the mixture as a carbon source, and the amount of carbon dioxide added is a water quality sensor disposed in the middle of the transfer pipe 3, and the mixture detected by the water quality sensor. It can be determined based on the carbon dioxide concentration in the medium. Furthermore, in the adjustment tank 4, based on the temperature of the mixture detected by the water quality sensor, the temperature of the mixture may be adjusted by a charging temperature controller.
　また、図２に示すシステムにおいて、調整槽４の底は、各バッグリアクター１よりも高い位置になるようにされている。この結果、前記脱ガス処理後、真空ポンプ５の作動を停止し、外気を調整槽４に導入することにより、調整槽４内の前記混合物をその自重により移送管３を介してバッグリアクター１に移送することができる。移送管３は、前記混合物をバッグリアクター１から調整槽４へ移送する際に用いた移送管３と同一である。 Further, in the system shown in FIG. 2, the bottom of the adjustment tank 4 is positioned higher than each bag reactor 1. As a result, after the degassing treatment, the operation of the vacuum pump 5 is stopped and the outside air is introduced into the adjustment tank 4, whereby the mixture in the adjustment tank 4 is transferred to the bag reactor 1 through the transfer pipe 3 by its own weight. Can be transported. The transfer pipe 3 is the same as the transfer pipe 3 used when transferring the mixture from the bag reactor 1 to the adjustment tank 4.
　この結果、図２に示すシステムによれば、図１に示すシステムと同様にして前記微細藻類の培養を行うことができ、前記生育期間と前記調整期間とを繰り返すことにより、液体培地２の撹拌及び酸素の除去を行うことができる。 As a result, according to the system shown in FIG. 2, the microalgae can be cultured in the same manner as the system shown in FIG. 1, and the liquid medium 2 is stirred by repeating the growth period and the adjustment period. And oxygen can be removed.
　また、図２に示すシステムでは、バッグリアクター１内の液体培地２の上方に空間６を設け、空間６にキャリア気体として空気を導入する気体導入管７ａと、空間６からキャリア気体を排出する気体排出管７ｂとを備えるようにすることもできる。このようにするときには、気体導入管７ａから導入されるキャリア気体を空間６内に流通させ、気体排出管７ｂから排出することにより、前記微細藻類が発生する酸素を空間６に放出させ、該キャリア気体によりバッグリアクター１外に排出することができる。 In the system shown in FIG. 2, a space 6 is provided above the liquid culture medium 2 in the bag reactor 1, a gas introduction pipe 7 a that introduces air as a carrier gas into the space 6, and a gas that discharges the carrier gas from the space 6. A discharge pipe 7b can also be provided. When doing so, the carrier gas introduced from the gas introduction tube 7a is circulated in the space 6 and discharged from the gas discharge tube 7b, thereby releasing oxygen generated by the microalgae into the space 6, and the carrier It can be discharged out of the bag reactor 1 by gas.
　従って、前記生育期間中にバッグリアクター１内で液体培地２中の溶存酸素濃度を低減することができ、該生育期間をより長くすることができる一方、バッグリアクター１から調整槽４への前記混合物の移送回数を低減することができる。 Accordingly, the dissolved oxygen concentration in the liquid medium 2 can be reduced in the bag reactor 1 during the growth period, and the growth period can be further increased, while the mixture from the bag reactor 1 to the adjustment tank 4 is increased. The number of times of transfer can be reduced.
　尚、本実施形態では、バッグリアクター１が水平方向に配置される横型の生育容器である場合について説明しているが、バッグリアクター１は垂直方向に配置される縦型の生育容器であってもよい。 In this embodiment, the case where the bag reactor 1 is a horizontal growth container arranged in the horizontal direction has been described. However, the bag reactor 1 may be a vertical growth container arranged in the vertical direction. Good.
　１…バッグリアクター（生育容器）、　２…液体培地、　４…調整槽。 1 ... bag reactor (growth vessel), 2 ... liquid medium, 4 ... regulation tank.

Claims (7)

  1. 　下記の工程（１）～工程（４）を備え、所定の生育期間には工程（１）を行い、且つ、工程（２）～工程（４）は行なわず、工程（１）を行った後に所定の調整期間には少なくとも工程（２）～工程（４）を行い、前記生育期間と前記調整期間とを繰り返すことを特徴とする微細藻類の培養方法。
    工程（１）：微細藻類を外気から隔離されるように構成された閉鎖式の生育容器に入れ、該生育容器に収容された液体培地中で光独立栄養的に生育させる。
    工程（２）：前記工程（１）において前記微細藻類を生育させた前記液体培地の少なくとも一部又は全部を該微細藻類ごと前記生育容器から調整槽に移送する。
    工程（３）：前記工程（２）において前記調整槽に移送した前記微細藻類及び前記液体培地の混合物を該調整槽内で脱ガス処理する。
    工程（４）：前記工程（３）において脱ガス処理した前記微細藻類及び前記液体培地の混合物を前記調整槽から前記生育容器に移送する。     The following steps (1) to (4) are provided, the step (1) is performed during a predetermined growth period, and the steps (2) to (4) are not performed and the step (1) is performed. A method for culturing microalgae, comprising performing at least steps (2) to (4) in a predetermined adjustment period, and repeating the growth period and the adjustment period.
    Step (1): Microalgae are placed in a closed growth container configured to be isolated from the outside air, and grown in a photoautotrophic manner in a liquid medium contained in the growth container.
    Step (2): At least a part or all of the liquid medium on which the microalgae are grown in the step (1) is transferred from the growth vessel to the adjustment tank together with the microalgae.
    Step (3): The mixture of the microalgae and the liquid medium transferred to the adjustment tank in the step (2) is degassed in the adjustment tank.
    Step (4): The mixture of the microalgae degassed in the step (3) and the liquid medium is transferred from the adjustment tank to the growth vessel.
  2. 　請求項１記載の微細藻類の培養方法において、前記生育容器は水平方向に配置される横型の容器であることを特徴とする微細藻類の培養方法。 2. The method for culturing microalgae according to claim 1, wherein the growth vessel is a horizontal vessel arranged in a horizontal direction.
  3. 　請求項１記載の微細藻類の培養方法において、前記微細藻類を生育させている前記液体培地の溶存酸素濃度に基づいて、前記生育期間から前記調整期間への移行時期を決定することを特徴とする微細藻類の培養方法。 2. The method for culturing microalgae according to claim 1, wherein the transition period from the growth period to the adjustment period is determined based on the dissolved oxygen concentration of the liquid medium in which the microalgae are grown. Microalgae culture method.
  4. 　請求項１記載の微細藻類の培養方法において、前記生育容器を水面下又は海面下に浮遊させて、前記微細藻類を光独立栄養的に生育させることを特徴とする微細藻類の培養方法。 2. The method of culturing microalgae according to claim 1, wherein the microalgae are grown photoautotrophically by suspending the growth vessel below the water surface or the sea surface.
  5. 　請求項４記載の微細藻類の培養方法において、
    　前記生育容器は、一端に開口を有し、一部が伸縮性素材からなり、該開口に接続された移送管を介して前記調整槽に連通しており、
    　該調整槽を該調整槽の底が該開口より低い位置になるように沈降させることにより、前記微細藻類及び前記液体培地の混合物を自重により前記調整槽に移送し、
    　該調整槽を該調整槽の底が該開口より高い位置になるように上昇させることにより、前記微細藻類及び前記液体培地の混合物を自重により前記生育容器に移送することを特徴とする微細藻類の培養方法。     The method for culturing microalgae according to claim 4,
    The growth container has an opening at one end, a part is made of a stretchable material, and communicates with the adjustment tank through a transfer pipe connected to the opening,
    By allowing the adjustment tank to settle so that the bottom of the adjustment tank is lower than the opening, the mixture of the microalgae and the liquid medium is transferred to the adjustment tank by its own weight,
    The microalgae is characterized in that the mixture of the microalgae and the liquid medium is transferred to the growth vessel by its own weight by raising the adjustment tank so that the bottom of the adjustment tank is higher than the opening. Culture method.
  6. 　請求項１記載の微細藻類の培養方法において、前記生育容器に収容された前記液体培地の上方に空間を設け、該空間にキャリア気体を流通させて、前記微細藻類の生育により該空間内に溜まった酸素を排出することを特徴とする微細藻類の培養方法。 2. The method for cultivating microalgae according to claim 1, wherein a space is provided above the liquid medium accommodated in the growth vessel, and a carrier gas is circulated in the space so that the microalgae accumulate in the space due to the growth of the microalgae. A method for cultivating microalgae, characterized in that oxygen is discharged.
  7. 　請求項１記載の微細藻類の培養方法において、前記生育容器を複数設けることを特徴とする微細藻類の培養方法。 The method for culturing microalgae according to claim 1, wherein a plurality of the growth vessels are provided.
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JPH09121835A (en) * 1995-10-27 1997-05-13 Chikyu Kankyo Sangyo Gijutsu Kenkyu Kiko Tubular-type photobioreactor
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JPS59156279A (en) * 1983-02-28 1984-09-05 Takashi Mori Photo-synthetic reactor
JPH09121835A (en) * 1995-10-27 1997-05-13 Chikyu Kankyo Sangyo Gijutsu Kenkyu Kiko Tubular-type photobioreactor
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