In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce
the energy consumption of lipid extraction process and improve the conversion yield of the microalgae
biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for
the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to
75% ethanol volume ratio 1:2, mixed solvent dosage 6.0 mL, reaction temperature 90 C, reaction time
2.0 h and catalyst volume 0.6 mL, the direct transesterification process of microalgal biomass resulted
in a high conversion yield up to 90.02 ± 0.55 wt.%.
Biodiesel profile at 30 C temperature is well supported by higher saturated fatty acids (SFA) to unsaturated
fatty acids (USFA) ratio. GP operation showed good COD and nutrient removal concomitant to the
biomass growth.
2014