filtration through bolting-silk in 200 mesh, dried to constant
weight at minus 50 C in lyophilizer (FDU-1200, EYELA, Japan),
and then ground to homogeneous powder to analyze its lipid. Total
lipid of algae biomass was quantified gravimetrically following the
extraction using a chloroform/methanol mixture (2/1, V/V) (Song
et al., 2013). After the two-step in situ methyl esterification
process, the fatty acids properties were examined through the
GC–MS method as described by Ji et al. (2014). The biomass productivity
(mg L1 d1) of microalgae in each group was calculated
according to the following formula (Ji et al., 2014):