Effect of Culture Conditions on Fatty-Acid Composition of Heterosigma akashiwo

Heterosigma akashiwo, which contains large amounts of polyunsaturated fatty acids, might be a natural source of such fatty acids for foods and pharmaceuticals. We studied the effect of culture conditions on the fatty acid composition of this plankton. The total fatty acid content of cells grown at 17°C was 50% (w/w) higher than that of cells grown at 25°C. The fatty acid composition was affected by the culture pH and temperature and by the addition of NaCI. In cells grown at 25°C, C 20: 5 accounted for 20% of total fatty acids; in cells grown at 29°C, the proportion was 11% (w/w). The greatest accumulation of C 18: 4 was at pH 5.8 with temperature at 17 or 29°C,and the NaCI concentration of 1.6%.