Effect of environmental conditions on the fatty acid composition of the green alga Chlorella sorokiniana SHIHIRA et KRAUSS

The effects of temperature, light intensity and growth phase on the fatty acid composition of Chlorella sorokiniana were investigated using autotrophic cultures. The increasing cultivation temperature up to 35 °C was accompanied by the significant increase of C16/C18 ratio and decrease of unsaturated to saturated fatty acids ratio. The proportion of polyunsaturated fatty acid (PUFA) was doubled from 25 °C to 35 °C. Light intensity has no significant effect on fatty acid composition, but a small increase of the unsaturation degree as irradiance fell was observed. Changes were also found in the fatty acid composition with culture age. Stationary phase cultures showed increased proportions of saturated and monounsaturated fatty acids and reduced proportions of PUFA. The results demonstrate that the fatty acid composition and PUFA production in particular can be favourably manipulated by varying culture conditions.