Optimization of light intensity and photoperiod for Isochrysis galbana culture to improve the biomass and lipid production using 14-L photobioreactors with mixed light emitting diodes (LEDs) wavelength under two-phase culture system.

•I. galbana was cultured in 14-L photobioreactors using two-phase culture system.•Maximum biomass and lipid content was obtained with 18:6 h and 400 µmol/m2/s.•Maximum biomass and lipid content was 1.25 g dcw/L and 71.1% (w/w), respectively.•SFAs decreased as light intensity increases while and vice versa for UFAs.•Stearic acid (C18) was the most dominant fatty acid.