| 摘要 |
PROBLEM TO BE SOLVED: To culture a cocolithophorid alga to produce an increased amount of docosahexaenoic acid by inoculating a cocolithophorid alga in an inorganic liquid culture medium in a transparent vertical type flat water tank and carrying out a multi-stepped culture as light is irradiated under specific conditions as a CO2 -containing air is passed through until the PVC concentration reaches the upper limit. SOLUTION: When a kind of unicellular micro-alga producing a coccolith mainly comprising calcium carbonate (for example, Pleurochrysis culthere) is cultured in an inorganic liquid culture medium in a transparent vertical type flat water tank under irradiation of light as a carbon dioxide-containing air is passed through, this culture process is divided into the following three steps: in the first step, coccolithophorid is cultured under irradiation with light from one of the front or rear face of the water tank with 3,000-4,000lx from 0.1-0.4ml/l of PCV concentration to 0.5-1ml/l; in the second step the coccolithophorid of the final concentration in the first step is cultured under irradiation with the same luminance as in the first step from both of the front and rear faces until the PCV concentration reaches 2.0-2.3ml/l; and in the third step the alga is cultured under irradiation with 5,000-6,000lx from both faces until the PCV concentration comes up to 5.0-5.5ml/l whereby docosahexaenoic acid is obtained in a large amount. |
