JP2526360B2 - Method for culturing filamentous algae - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for culturing filamentous algae, and more particularly to a method for culturing filamentous algae, which facilitates the recovery of these algae from the culture solution after culturing the filamentous algae. .

[0002]

2. Description of the Related Art In recent years, attention has been paid to CO ₂ fixation by high-volume culture of algae and production of high-quality proteins. When a useful substance in an alga is produced by culturing algae, a solid-liquid separation step of recovering the alga after culturing from the culture solution is required. The liquid separation process has become a big problem. That is, in a small-scale culture in a laboratory or the like, it is possible to collect only the algal cells by removing the culture solution by suction filtration or by sedimenting the algal cells by centrifugation. However, large-scale culture requires a large culture area and a large amount of culture solution, and if the alga bodies are recovered by a filtration method or a centrifugation method after the culture, high energy and high cost are required. It was practical.

Further, as a method for recovering algal bodies in a large-scale culture of algae, a method of utilizing the property that algal bodies naturally float in the culture solution, collecting a concentrated liquid of the floating algal bodies, and drying it directly (Algae Biowass: 'Ruoaloriented fresh wate
r culitivation and production of algae in India '
IV Venkataiaman, BP Nigam and PK Ramanath
an), a flocculant such as aluminum sulfate or calcium chloride is added to the culture solution to flocculate the alga cells and perform solid-liquid separation (Advances in Biotechnological Process 6, pages 7
3-110) and the like have been proposed.

However, in the former method, the concentrated liquid of the algal cells that has floated up cannot be scooped out unlike the aggregates, so the concentrated liquid must be dried directly, and it takes a long time to recover the algal cells. In the latter method, the culture is contaminated by the use of the aggregating agent, and when the alga body or its extract is used as a food or a drug, the incorporation of the aggregating agent may be a problem.

[0005]

The object of the present invention is to solve the above-mentioned problems of the prior art and to collect filamentous algae after culturing efficiently and without contamination from the culture broth. The purpose of the present invention is to provide a method for culturing.

[0006]

The above object is to add a porous carrier or a fibrous carrier to an algae culture solution, to cause a swirling flow at a constant speed to form an agglomerate in an algal body, and the agglomerate to be a carrier. It is achieved by accumulating in. That is, the invention claimed in the present application is as follows. (1) When culturing filamentous algae in a culture solution, a porous carrier or a fibrous carrier is added to the culture solution, and the culture solution is swirled at a flow rate of 13 to 32 cm / sec. Culture method.

[0007]

The algal cells cultured by the swirling of the culture solution are drawn into the center of swirling or the bottom of the culture vessel and aggregate at these places to form aggregates. Since this aggregate precipitates in the culture medium, it can be easily collected. In particular, filamentous algae are entangled with each other and aggregate at a higher level, which improves the recovery efficiency. Further, by adding a carrier to the culture solution and swirling, the alga bodies gathered in the swirling center contact the carrier flowing into the center, and can accumulate in the pores of the carrier or become entangled in the fibers of the carrier, Aggregation of alga bodies is facilitated, and recovery of alga bodies from the culture solution is further facilitated.

The algae used in the culture method of the present invention are filamentous
Body algae, for example, Spirulina s
p.) and the genus Anabaena (Anabaena sp.) and the like. Algae
Is a known medium such as K₂HPO_Four, NaNO₃,
FeSO_Four, MgSO_Four, K₂SO_Four, NaCl, Ca
Cl, H₃BO₃, MnCl₂, ZnSO _Four, CuSO
_Four, Na₂MoO_Four, NH_FourVO₃, Co (NO₃)₂,
NiSO_FourInorganic salts such as 5.0 to 2,500 ppm and
And organic nutrients such as vitamins and amino acids 0.1 to 50 p
Culture using any liquid medium (culture medium) containing PM
Can be. As a typical basal medium, Zaluk (Za
rrouk) medium and the like.

CO ₂ gas or NaHCO ₃ is added to the medium as a CO ₂ source necessary for photosynthesis. Usually 0.0
1-30%, preferably 1-20% CO ₂ gas or 0.1-10%, preferably 0.5-5% NaHCO 3.
₃ is added. The culture temperature is preferably 5 to 60 ° C, particularly preferably 20 to 40 ° C. The illuminance of light during culture is usually 1
Maintained at 00-100,000 lux, but especially 500
~ 30,000 lux is desirable. Fluorescent lamp, X
Although an e-lamp or the like is used, a filter or the like may be used to limit the wavelength of light reaching the alga.

In the present invention, the culture is cultivated by causing a swirling flow. The method of generating the swirling flow is not particularly limited, and a method of swirling the incubator itself using a rotary shaker or the like and a method of swirling only the culture solution are adopted. The latter method uses a circulation system in which the culture solution discharged from the culture vessel is again swirled, and a system in which the culture solution containing waste products in the culture vessel is discharged and a fresh culture solution is replenished. Examples thereof include a method of utilizing, and specifically, a method of culturing in a culture tank using the principle of hydrocyclone. Further, when blowing CO ₂ gas directly into the culture vessel, a swirling flow can be generated by utilizing this aeration system.

The rotation speed of the culture solution is 13 to 32 cm / s.
ec. When the swirling speed is outside this range, aggregates of filamentous algae cannot be formed during culture. For example, a shaker with a shaking width of 2.5 to 5.0 cm and a bottom diameter of 8.5
20 rpm to 8 cm when shaking a cm flask
It is preferable to rotate at 0 rpm, particularly 30 rpm to 70 rpm. The swirling flow may be a continuous flow or an intermittent flow.

[0012] In yet present invention, promote aggregation of putting a carrier algal culture solution to pivot. Suitable carriers include porous materials such as polyurethane foam, sponge, and silicone, and fibrous materials such as felt, loofah (vegetable fiber), and glass fiber. Sponge with a pore diameter of 100 to 2000 μm is particularly suitable for filamentous algae. Is suitable. The shape of the carrier is not particularly limited, but a sphere or a polyhedron having a diameter of 0.5 to 10 cm, which is finely chopped or cut to have a large surface area, is preferable. The amount of the carrier used is preferably about 0.5 to 50%, and particularly preferably 1 to 10% of the culture solution volume. In addition, the carrier may be added to the culture solution at the start of the culture for culturing, or may be added at the latter stage of the culturing for collecting the alga. The aggregated alga bodies accumulate in the carrier pores and precipitate in the culture solution as aggregates, so they can be easily collected.

[0013]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. Example 1 NaHCO ₃ 1 as a CO ₂ source in Zarrow medium
The liquid medium containing 6.8 g / l was added to the filamentous alga Sp
irulina SP. 0.15 g (dry weight) / l
Then, a sponge (pore size: 500 μm) cut into 1 cm squares was put into the cells to culture. A flask with a bottom diameter of 8.5 cm was used as the incubator, and this was shaken by a rotary shaker to 60
A swirling flow of rpm (swirl speed 13 cm / sec) was generated to aerate the liquid medium with air. The culture temperature was maintained at 23 ° C and the illuminance was maintained at 13,000 lux . Turn immediately after the start of culture
There is a bottom concentration area of algal cells in the center of the
The body begins to accumulate in the pores of the sponge, and after about 6 days the sponge
The entire surface of Ji was covered with algal bodies. 6 days from the start of culture
The subsequent culture state is shown.

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

Comparative Example 1 In Example 1, Syne which is a rod-shaped alga as the alga
chococcus SP. (0.1 g / l , dry weight )
Culture was performed in the same manner as in Example 1 except that However, algal cells were not accumulated in the sponge pores even after 6 days of culture. FIG. 2 shows the culture state 6 days after the start of culture.

[0023]

According to the present invention, the culture solution is swirled at a specific speed, and a porous carrier or a fibrous carrier is added to the culture solution for swirling, thereby aggregating algal cells during culturing. Since it can be accumulated in the carrier, solid-liquid separation of algal cells after culturing can be efficiently performed, and since no agent such as a flocculant is used for collecting algal cells, the safety of algal cells and their extracts is safe. Therefore, it is possible to economically perform large-scale culture.

[Brief description of drawings]

FIG. 1 is a diagram showing a culture state on day 6 after the start of culture in Example 1.

FIG. 2 shows the culture state on day 6 after the start of culture in Comparative Example 1 .
FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid culture medium (culture liquid) , 3 ... Aggregate of alga bodies, 4 ... Dispersed alga bodies, 5 ... Sponge, 10 ... Flask (culture container).

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shigeya Yoneya 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Toyo Kaiji Building 8F (72) Inventor Kazuki Kobayashi 2-8-11 Nishi-shinbashi, Minato-ku, Tokyo 7th Toyo Kaiji Building 8F (56) Reference JP-A-2-18000 (JP, A) JP-B-46-21782 (JP, B1)

Claims (1)

(57) [Claims] 1. When culturing filamentous algae in a culture solution, a porous carrier or a fibrous carrier is added to the culture solution, and the culture solution is swirled at a flow rate of 13 to 32 cm / sec. Method for culturing body algae.