Meanwhile, the analysis of the product yield was carried out by gas chromatography (GC) equipped with an FID detector. A highly polar capillary column BPX 70, SGE Company (length: 30 m, ID: 0.25 mm and capillary: 0.25 mm) was used for the separation of the FAME compounds. The n-hexane was used as the solvent for the dilution of the product samples and FAME Standard. 500 ppm of each standard methyl oleate, methyl palmitate, methyl linoleate, methyl myristate and methyl stearate were prepared as the reference standard. Meanwhile, methyl heptadecanoate was used as the internal standard and prepared together with the sample product. Then, 1 mL of the sample solution was injected into the GC injector port. The GC injector port was set at 230 C and the detector temperature was 270 C. However, the GC oven was programed with the increasing starting temperature from 100 C up to 250 C with 10 C/min of the temperature rate. The formula to calculate the product yield was as depicted in Eq. (2).