2.3. FAEE yield determined by GC analysis To quantify the FAEE yield from the direct transesterification reaction, gas chromatography (GC, Shimadzu GC-2010 Gas Chromatography, Japan) was used. DB-1 capillary column (0.25 mm 15 m; J and W Scientific, USA) and a FID detector were used for sample analysis. Sample and a standard solution (heptadecanoic acid ethyl ester) were diluted with 1 mL n-hexane. The FAEE conversion yield was analyzed by GC. Based on the maximum FAEE yield from lipids in Chlorella spp. described in Section 2.2, the conversion yield could be obtained by dividing the weight of FAEE obtained from each sample by maximum weight of FAEE obtainable