Lipid extraction from Nannochloropsis sp. microalgae for biodiesel production using supercritical carbon dioxide

Abstract

In this paper, microalgae lipid extractions were performed using conventional organic solvent and supercritical carbon dioxide (SC-CO2) for biodiesel-convertible lipid fractions. The highest levels (58.31%) of fatty acid methyl ester (FAME) content in the lipid extracted by SC-CO2 was obtained, and 18.0 wt.% crude lipid yield was achieved for Bligh-Dyer method. In the SC-CO2 extraction, methanol as a co-solvent was applied to increase the polarity of extract. The experimental results indicated that crude lipid yield, FAME content and yield extracted by combination of SC-CO2 with methanol were 12.5 wt.%, 56.32% and 7.04 wt.%, respectively, and this method could reduce the extraction time from 2 hour to 30 min when compared to SC-CO2 extraction. Therefore, SC-CO2 extraction is proven to be an environmentally-friendly and an effective method for lipid extraction from microalgae.