Effect of light intensity and photoperiod on biomass and fatty acid composition of the microalgae, Chlorella vulgaris

The effects of irradiance and photoperiod on the biomass and fatty acid (FA) composition of Chlorella vulgaris were examined in the exponential growth phase. Results indicated significant differences in biomass and FA at different intensities and photoperiods. Maximum biomass (2.05 +/- A 0.1 g l(-1)) was at 62.5 mu mol photons m(-2) s(-1) and 16:8 h light/dark photoperiod. FA composition changed considerably in different light regimes; the maximum percentage of total saturated (SFA) (33.38%) was recorded at 100 mu mol photons m(-2) s(-1) and 16:8 h photoperiod, while monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids decreased with increasing irradiance and light duration. The maximum percentage of total MUFA (15.93%) and PUFA (27.40%) was recorded at 37.5 mu mol photons m(-2) s(-1) and 8:16 h photoperiod.