The collected extract was evaporated
at 40 °C, dried at 70 °C for 2 h, and subsequently weighed after cooling to the room temperature. Lipid content of microalgae was calculated by dividing the residue weight by the freeze-dried
cell weight. Gas chromatography (HP 6890, USA) equipped with 30 m DBWAXETR
(J&W, Agilent) capillary column was used for qualitative and quantitative determination of fatty acid composition. The oven temperature program started at 190 องศาเซลเซียส, increase at 4 °C min-1 until
220 °C Carrier gas, N2, was kept at a constant rate of 15 mL/min. Injector and detector (flame ionization) temperature were kept at 220 °C. The fatty acid methyl ester (FAME) was prepared by adding 2 mL 2 N KOH in methanol solution to the sample for saponification.