JPH05184347A - Algae cultivator and its culture - Google Patents

Abstract

PURPOSE:To carry out mass culture of an alga while readily controlling the temperature and the irradiation light volume and effectively preventing contamination with a foreign material, etc., by using a specified apparatus. CONSTITUTION:An alga-culturing pond 2 is set in an air-doom type greenhouse 3 covered with a sunlight-transmitting film, capable of taking in the air by a fan 4 and designed so as to keep the inside to a positive pressure. The irradiation light volume is adjusted by using a low light-transmitting film or a light- screening sheet and the temperature is controlled by ventilation heating, etc. A filter is set to the air inlet of the air doom so that the inside of the cultivator 1 may be filled with a pure air and kept to a positive pressure. Thus, the objective culture is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cultivating algae comprising an algae culture pond and an air-dome type greenhouse covering the culture pond, and a method for cultivating algae using the culture apparatus.

[0002]

2. Description of the Related Art The most important factor in commercial production of algae is how to irradiate light inexpensively and efficiently. Most conventional algae culture devices use sunlight as a light source. It was also installed outdoors. However, when cultivating microalgae outdoors, keep the culture temperature in the optimum range for the algae to grow, and also to feed the algae, especially microbes and other algae that competitively inhibit photosynthesis. It was very difficult to prevent the contamination. Therefore, the only microalgae that have succeeded in commercial production so far are chlorella, spirulina, and donariella, which are highly resistant to microbial contamination. I could only produce it.

On the other hand, when cultivating and producing algae outdoors, sometimes foreign matter is mixed in, but there is no effective means for preventing this, and conventionally, after a great deal of time and labor is spent in the post-treatment process, the inspection is performed. , Have been removed. However, the applications of the algae produced are food additives, feed additives, cosmetics, raw materials for pharmaceuticals, functional foods, etc., and the quality requirements for the produced algae are becoming severer year by year.

[0004]

In order to solve these problems, various types of algae culture devices such as tubular type and tank type have been devised up to now, but none have been put to practical use. The reason is that the device is complicated and costly, and it is impossible to sufficiently irradiate the culture solution with light.
For example, it is not possible to sufficiently prevent the contamination of microorganisms. Further, all of these culturing devices are hermetically sealed, and have a drawback that the gas exchange rate of oxygen and carbon dioxide is slow and the photosynthetic rate or respiration rate of algae is lowered.

The object of the present invention is to provide an algae which has a simple structure, a low manufacturing cost, easy temperature control, and which can effectively prevent contamination of foreign substances and foreign organisms without impairing the production rate of algae. To provide a culture device and a culture method.

[0006]

Means for Solving the Problems As a result of earnest research, the inventors of the present invention have shown that a glass frame greenhouse is covered by covering an algae culture pond with an air dome type greenhouse (hereinafter referred to as an air dome) made of a film that transmits sunlight. Compared to the above, the manufacturing cost is lower, the irradiation light amount can be adjusted, the temperature can be easily controlled, and commercial production is possible even in areas where it was difficult to culture algae due to low temperature. I found it.

Further, by installing an air filter at the air intake of the air dome, the inside of the culture device is maintained at a positive pressure with clean air, which is cheaper and more efficient than other methods, and the production rate of algal cells is higher. The present invention has been completed by discovering that contamination of microorganisms or foreign substances can be prevented without impairing the above.

[0008]

More specifically, the present invention relates to an algae culture apparatus comprising an algae culture pond and an air-dome type greenhouse covering the culture pond, and a method for algae culture using the culture apparatus.

More specifically, the present invention comprises a culture pond for cultivating algae, and an air-dome type greenhouse in which the culture pond is covered with a sunlight-permeable film and which is provided with an air intake port and an exhaust port. An algae culture device characterized by
This is a culture device that adjusts the amount of light by selecting a film having an appropriate light transmittance as a film that transmits sunlight, or by laminating a film having a low light transmittance or a light shielding sheet on an existing film.

A method for adjusting the ventilation rate of the air dome,
By spraying mist-like water inside the air dome and adjusting the temperature inside the dome by the heat of vaporization, or by heating or cooling the inside of the culture pond or culture device, the temperature inside the culture pond or culture device can be adjusted. It is a culture device for algae, which is controlled or a combination thereof is used to control the temperature inside the culture device or in the culture pond. Furthermore, it is an apparatus for cultivating algae, characterized in that an air filter is provided at the air intake port of these culturing apparatuses, and a method for cultivating algae using the apparatus for cultivating algae, in particular, algae are Chlorella, Spirulina, Donariella, Fol This is a method for culturing algae such as microalgae such as Firidium and Haematococcus.

Next, the culture apparatus according to the present invention and the method for cultivating algae using the culture apparatus will be described with reference to the drawings.
The details will be described. The algae culture pond (2) used in the present invention may be in any shape as long as it is suitable for the production of the target algae, and a culture pond having any shape can be used in the present invention. For example, a circular culture pond used for culturing Chlorella or the like, a raceway-type culture pond used for culturing Spirulina or the like, or a lagoon-type culture pond used for culturing Donariella or the like.

The air dome (3) used in the present invention is
The blower (4) takes in air and keeps the inside at a positive pressure to inflate the sunlight-permeable film (5) to retain the structure, which can completely cover the culture pond (2). Any structure may be used as long as it is possible. For example, an air tent house (Japanese Patent Publication 1-54006) and the like can be mentioned.

The air dome (3) is most suitable for use in the present invention because it is superior to any other type of greenhouse such as a glass frame greenhouse or a vinyl house in the following points. That is, since the structure is simple, the device cost and maintenance cost are low,
Not only is it easy to install and maintain, it can also be easily installed in existing culture ponds. Since the column that holds the glass or film required in a glass frame greenhouse or vinyl house is unnecessary, high light transmittance, high photosynthetic rate can be obtained, and when the amount of light is too large and unsuitable for culture, The amount of light can be easily adjusted by stacking a light-shielding sheet or the like on the film (5) or by selecting a film (5) having an appropriate light transmittance. The light-shielding sheet referred to in the present invention is a sheet made of a material having a low light transmittance, or a mesh-like sheet, which is usually used to limit the light transmittance.

Compared with a normal greenhouse, an air dome has a high ventilation rate, and therefore a high gas exchange rate of oxygen and carbon dioxide, and a high production rate can be obtained without inhibiting photosynthesis or respiration. When culturing algae, unlike land plants, gas exchange takes place via the water surface, so the exchange rate is slow, which limits the production rate of algal bodies. For example, according to the research conducted by the present inventors, when spirulina is cultured in an outdoor pond, the amount of dissolved oxygen in the culture solution during the day is 2 times the saturated dissolved oxygen concentration in the solution at the atmospheric pressure and the temperature. Or tripled. This indicates that the oxygen produced by photosynthesis from spirulina causes the dissolved oxygen concentration in the liquid to be extremely high, but if the dissolved oxygen concentration in the liquid becomes too high, it inhibits the growth of algae. It is known to affect. Therefore, it is important to increase the ventilation rate to increase the gas exchange rate on the water surface, and the air dome (3) is optimal for a greenhouse that can meet this requirement.

Since a constant air flow is generated inside the culture device (1), the temperature or gas concentration inside the dome can be kept uniform, control is easy, and stable algae production is possible. Film (5) of the air dome (3) used in the present invention
As described above, a material having a light transmittance that allows sunlight to pass therethrough and obtains a light amount suitable for the properties of the cultured alga is selected. In addition, it is desirable to use a material that has as high mechanical strength and weather resistance as possible, and the surface of which does not easily get dirty. For example, a film in which a nylon thread mesh is sandwiched with a vinyl chloride film and the surface is acrylic coated is preferably used.

The temperature control of the algae culture device (1) comprising the culture pond (2) and the air dome (3) is performed as follows. That is, since the air dome (3) is a greenhouse, the inside temperature is usually higher than the outside temperature, but the temperature difference is small when the ventilation rate is high, and is large when the ventilation rate is low. Therefore, the ventilation rate is adjusted. By doing so, the temperature inside the culture device (1) can be easily adjusted. If necessary, it is also possible to combine various heating devices such as boilers and heaters to raise the temperature inside the dome, and by circulating the medium and heating the inside of the culture device or the culture pond,
It is also possible to control the temperature inside the culture device or in the culture pond.

Since it is possible to easily control the temperature in this way, it is clear that commercial production of algae is possible even in an area where it has been difficult to culture due to the low temperature. It can fluctuate greatly throughout the year and may exceed the optimum temperature depending on the season. In that case, in addition to the method of increasing the ventilation rate, a method of stacking a suitable light-shielding sheet on the film (5) of the air dome (3) to shield light, cooling water is circulated by using a chiller, etc. ) Or a method of cooling the inside of the culture device (1) or the like to lower the water temperature of the culture pond (2). However, it is desirable to use a method that is inexpensive and that allows the temperature to be adjusted by a simple operation. For example, a method of spraying mist-like water inside the air dome and lowering the temperature inside the dome by heat of vaporization is preferable. Also in this case, according to the present invention, it can be easily performed by injecting water into the air blown into the air dome.

The air filter (7) provided at the air intake (6) of the air dome efficiently removes the foreign matter and foreign substances of interest, and the pressure loss in the air filtration causes an excessive load on the blower (4). It is necessary to have a sufficient filtration capacity so as not to apply Any material may be used as long as it is a filter satisfying this condition. For example, in order to remove insects and large foreign substances, a wire net, an insect net, etc. may be mentioned. In addition, for example, when the target is micro organisms or dust, a sponge or a non-woven fabric filter, and if you want to keep the inside sterile, you can use a more advanced filtration filter such as a HEPA filter, and if necessary, combine these. It is preferable to use.

Further, in order to keep the inside of the culturing device (1) clean, it is desirable to provide an air filter at the exhaust port (8) as well, and for floors other than the concrete culturing pond, concrete floors ( It is desirable to be completely covered with 9). In addition, the drainage ditch (1
0) is preferably installed, and further, it is desirable that the soil has a slope descending toward the drainage channel so that drainage can be easily performed, and a drainage pipe (11) leading to the outside of the culture device in the middle of the drainage channel. It is desirable to have. The dirt floor (9) and the culture pond (2) made of concrete or the like can be easily washed and sterilized by spraying a germicide such as an aqueous solution of sodium hypochlorite in a liquid or mist form.

As described above, the algae culturing apparatus (1) whose inside is kept clean and whose irradiation light quantity and temperature are controlled is
Although it can be used for culturing all algae, it is particularly suitable for culturing microalgae such as Chlorella, Spirulina, Donariella, Forfilidium, and Hematococcus.

Chlorella is currently produced in Taiwan and Japan. The algae strains used in the culture are Chlorella pyrenoidosa, Chlorella pyrenoidosa, C. ellipsoidea, Chlorella vulgaris, or Scenedesmus.
In s), etc., the optimum temperature for culturing varies greatly among species and strains, and strains that are suitable for the climatic conditions of each production area are selected and produced. For example, in Japan, the optimal temperature for growth is 25 ° C, such as Chlorella pyrenoidosa (C. pyrenoidosa), and in Taiwan, the optimal temperature is 35-40 ° C for Chlorella Epseidea (C.
ellipsoidea) is used. However, it is difficult to keep the water temperature at an appropriate temperature in winter in any of the production areas, and the production efficiency in winter is low. Therefore, by using the algae culture device according to the present invention, the production efficiency in winter can be significantly improved.

Spirulina is produced in Thailand, the United States (California, Hawaii), Mexico and Japan. Spirulina used for culture
Since the optimum temperature for algae strains is 35 ° C, it is possible to maintain high productivity throughout the year because the average temperature is 30 throughout the year like Thailand.
Only in areas where the temperature exceeds ℃. Therefore, by using the apparatus for cultivating algae according to the present invention, it is possible to significantly improve the production efficiency in winter in the area.

Donariella is produced in Australia and Israel. Donaliella salina (Dunaliella salina) and Donaliella valdavir (D. bardawil), which are used for culturing, all have salt tolerance, and are used in commercial production to prevent the contamination of predatory microorganisms such as amoeba. Cultured at a high salt concentration of over%. Therefore, by using the algae culture device with an air filtration filter according to the present invention, the salt concentration can be reduced without contaminating microorganisms, the chemicals for the medium can be significantly saved, and the desalting process from the obtained product can be simplified. Can be converted. In addition, the ease of production in areas other than the above is the same as for Chlorella and Spirulina.

Phorphyridium is a unicellular red alga and is expected as a red natural pigment phycoerythrin producing alga with a good color tone, but it has not yet reached commercial production. One of the reasons is that the optimum temperature for growth is as low as 25 ° C. It is difficult to find a production site suitable for commercial production that can maintain the water temperature around 25 ° C throughout the year, but if the algae culture device according to the present invention is used, even in temperate regions such as Japan, for example, throughout the year It is possible to produce.

Hematococcus is expected as a carotenoid pigment / astaxanthin-producing alga with high added value, but it has not yet reached commercial production. The first reason is that the algae are easily supplemented by contaminating microorganisms, and secondly, the optimum temperature for growth is low as in Phorphidium. Therefore, if the algae culture device with an air filtration filter according to the present invention is used, the temperature is appropriate.
The temperature can be controlled at 25 to 30 ° C, the contamination of microorganisms can be efficiently prevented without impairing the production rate of algal cells, and stable culture can be performed.

In the case of any algae, by providing an air filter at the air intake of the air dome, it is possible to obtain a high quality algal body free from foreign matter.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 A raceway-type culture pond P1 (1000 m ² ) which has been producing spirulina only in summer until now.
I installed an air dome. First, dig a groove around the pond,
Next, a film that transmits sunlight was spread on the pond, and a mesh holding the film was spread on it. Then, an air blower for air intake was tied to the air intake of the film, and the pedestal was fixed to the ground. The hem part of the film and mesh was embedded and fixed in a groove dug in advance. Finally, the blower was operated to expand the film.

When the temperature characteristics of the culture apparatus P1A in winter were examined, the water temperature in the culture pond was 10 on average as compared with P1.
℃, by burning propane gas and heating, the average temperature increased by 4 ℃. (Example 2) Using the culture basin P1A with an air dome constructed in Example 1, spirulina was produced during the winter season from November to March. The medium contains SO for Spirulina
Using T medium (Table 1) and culturing with pH adjusted to 9.0, the algal cell production rate was as shown in Table 3.

Table 1. Composition of SOT medium ───────────────── NaHCO ₃ 16.8 g / l K ₂ HPO ₄ 0.5 g / l NaNO ₃ 2.5 g / l K ₂ SO ₄ 1.0 g / l NaCl 1.0 g / l MgSO ₄・ 7H ₂ O 0.2 g / l CaCl ₂・ 2H ₂ O 0.04 g / l FeSO ₄・ 7H ₂ O 0.01 g / l Na ₂ EDTA 0.08 g / l A5 solution 1.0 ml / l ─── ──────────────

Table 2. Composition of A5 solution ───────────────── H ₃ BO ₃ 2.86 g / l MnSO ₄・ 7H ₂ O 2.5 g / l ZnSO ₄・ 7H ₂ O 222 mg / l CuSO _{4 · 5H 2 O 79 mg /} l Na 2 MoO 4 · 2H 2 O 21 mg / l ─────────────────

(Comparative Example 1) Culture pond P1 without air dome
The production rate of spirulina in the winter season was clearly P1 as shown in Table 3 even when the same medium / PH as in Example 2 was used.
It was inferior to A.

[0032]

(Example 3) A concrete soil space was provided around a 30 m ² concrete raceway-type culture pond P2. An anchor for fixing the film of the air dome was embedded on the outside of the soil, and a drainage groove with a depth of 10 cm was provided on the inside. The soil has a slight slope toward the drain to improve drainage. A drainage pipe was installed at one end of the drainage channel to communicate with the outside. The air dome and blower were fixed to the anchor and the film was inflated. Nonwoven fabric filter PS300 (made by Japan Vilene Co., Ltd.) at the air intake
Attached. As described above, the culture apparatus P according to the present invention
2A was installed.

(Comparative Example 2) Up to now, it has been attempted to cultivate the green alga Haematococcus in P2, but on the 2nd to 3rd day after the initiation of culture, it was supplemented by microbes such as amoeba and ciliates, or insects such as aphids. It was impossible to grow algal bodies.

(Example 4) Hematococcus was produced using P2A. Using the modified C medium shown in Table 4, the pH was 7.
The culture was adjusted to 0. The pond inside the P2A and the soil were previously sterilized with an aqueous sodium hypochlorite solution. For culturing, Haematococcus pluvialis N4 strain (Haematoc
occus pluvialis N4) was used to obtain a clean seed alga strain that was not contaminated with other eukaryotic microorganisms by in-house culture and used for P2
A was inoculated. The water temperature was maintained at 25-29 ° C during the culture period.

As a result, Haematococcus grows smoothly,
The alga concentration reached 720 mg / l on the 7th day of culture. No contamination of small animals such as amoeba and ciliates or insects such as aphids was observed. Average algal production rate for 7 days is 9.4g / m
It was ² · day.

Table 4. Modified C Medium composition _{──────────────────── Ca (NO 3) 2 ·} 4H 2 O 0.3 g / l KNO 3 0.2 g / l β-Na 2 glycerophosphate _{0.1 g / l MgSO 4 · 7H} 2 O 80 mg / l Vitamine B 12 0.2 μg / l Biotin 0.2 μg / l Thiamine HCl 20 μg / l P IV metals 3 ml / l Tris (hydroxymethyl) aminomethane 0.5 g / l ── ──────────────────

Table 5. Composition of P IV metals ──────────────────── FeCl ₃・ 6H ₂ O 196 mg / l MnCl ₂・ 4H ₂ O 36 mg / l ZnSO ₄・ 7H _{2 O 22 mg / l CoCl 2 ·} 6H 2 O 4 mg / l Na 2 MoO 4 · 2H 2 O 2.5 mg / l Na 2 EDTA · 2H 2 0 1 g / l ──────────── ────────

[0039]

According to the apparatus for cultivating algae according to the present invention,
By covering the culture pond with an air dome, the amount of irradiation light can be adjusted and the temperature can be easily controlled.By installing an air filter at the air intake, it is possible to stabilize high-quality algal cells free from foreign matter and foreign organisms. It can be cultivated efficiently and enables the production of microalgae such as Phorphidium and Haematococcus, which could not be produced commercially until now.

[0040]

[Brief description of drawings]

FIG. 1 shows a front view of a culture device including a raceway-type culture pond and an air-dome type greenhouse as an example of the algae culture device according to the present invention.

FIG. 2 is a plan view of the culture device of FIG.

FIG. 3 is a partially enlarged vertical sectional view taken along the line IV-IV in FIG.

[0041]

[Explanation of symbols]

1 ... Algae culture device, 2 ... Algae culture pond, 3 ... Air-dome type greenhouse, 4 ... Blower, 5 ... Sunlight permeable film, 6 ... ... Air intake, 7 ... Air filter, 8 ... Exhaust, 9 ... Soil made of concrete, 10 Drainage, 11 ... Drainage pipe , 12 ... ・ Gateway, 13 ・ ・ ・ ・ Stirring turbine.

Claims (9)

[Claims] 1. An algae characterized by comprising a culture pond for cultivating algae, and an air dome type greenhouse which covers the culture pond with a film which transmits sunlight and which is provided with an air intake port and an exhaust port. Culture device. 2. The amount of light is controlled by selecting a film having an appropriate light transmittance as a film that transmits sunlight or by laminating a film having a low light transmittance or a light shielding sheet on an existing film. Algae culture device. 3. The algae culture device according to claim 1, wherein the temperature inside the culture device is adjusted by adjusting the ventilation rate of the air dome. 4. The apparatus for cultivating algae according to claim 1, wherein atomized water is sprayed inside the air dome, and the temperature inside the dome is adjusted by heat of vaporization to adjust the temperature inside the culturing apparatus. 5. The algae culture device according to claim 1, wherein the temperature inside the culture device or in the culture pond is adjusted by heating or cooling the inside of the culture device. 6. A light-transmitting film having an appropriate light transmittance is selected, or a film having a low light transmittance or a light-shielding sheet is overlaid on an existing film to adjust the light amount and the air dome of the air dome. By combining a method of adjusting the ventilation rate, a method of spraying mist-like water inside the air dome and lowering the temperature inside the dome by heat of vaporization, a method of heating or cooling the inside of the culture device or the culture pond, etc. The algae culture device according to claim 1, wherein the temperature of the inside or the culture pond is adjusted. 7. The apparatus for cultivating algae according to any one of claims 1, 2, 3, 4, 5 or 6, wherein an air filter is provided at the air intake of the air dome type greenhouse. 8. A method according to claim 1, 2, 3, 4, 5, 6 or 7.
A method for culturing algae using the apparatus for cultivating algae according to any one of 1. 9. The method for cultivating algae according to claim 8, wherein the algae are microalgae such as Chlorella, Spirulina, Donariella, Forfilidium, and Hematococcus.