Ionic liquid-mediated extraction of lipids from algal biomass.

Lipids from algal biomass were extracted using mixtures of ionic liquids (ILs) and methanol, and fatty acid profiles of the extracted lipids were characterized in this work. Mixtures of ILs and methanol successfully dissolved biomass leaving lipids insoluble. The total contents of lipids extracted from commercial and cultivated Chlorella vulgaris were 10.6% and 11.1%, respectively, by the conventional Bligh and Dyer's method, while a mixture of [Bmim][CF(3)SO(3)] and methanol extracted 12.5% and 19.0% of the lipids, respectively. Multi-parameter regression by the linear solvation energy relationship showed that dipolarity/polarizability and hydrogen bond acidity of ILs are more important than their hydrogen bond basicity for effectively extracting lipids from algal biomass. Fatty acid profiles of the lipids extracted using IL-methanol mixtures showed that C16:0, C16:1, C18:2, and C18:3 fatty acids were dominant. This suggests that the lipids extracted from C. vulgaris can be used as a source of biodiesel production.