Extracting Lipids from Several Species of Wet Microalgae Using Ethanol at Room Temperature

Recently, a novel method using ethanol was proposed for extracting lipids from wet Picochlorum sp. at room temperature and pressure. In this study, the feasibility of the method was assessed in several microalgae species with high moisture (Chlorella sp. 442, Chlorella sp. 725, and Picochlorum sp. 802). The result revealed that high lipid extraction yields (approximately 30% of the dry weight) were obtained when using ethanol, which were comparable to those obtained by the Bligh–Dyer method. For each species, no significant differences in terms of the distribution of lipid classes and fatty acid composition were observed based on the different extraction methods. These results demonstrated that the proposed procedure could be applied in extracting lipids from wet microalgae successfully. After lipid extraction, algal cells were damaged exhibited by pits and gaps, but the cell disruption efficiency was lower than 30%, suggesting that lipids were mainly released through pits and gaps, followed by cell lysis. Additionally, for each species, the wet lipid-extracted algal residues contained high protein content, which could be a promising source of high-value byproducts.