Extraction of proteins from the microalga Scenedesmus obliquus BR003 followed by lipid extraction of the wet deproteinized biomass using hexane and ethyl acetate.

A current problem of the lipid extraction from wet biomass is the formation of emulsions during the mixing of the microalgal biomass and organic solvents. It has been suggested that microalgal proteins play an important role in the formation and stability of such emulsions. Herein, the extraction of proteins of the freshwater microalga Scenedesmus obliquus BR003 was optimized for further extraction of lipids from the wet deproteinized biomass. The optimal (pH 12 at 60 °C for 3 h) and moderate (pH 10.5 at 50 °C for 2 h) conditions of protein extraction resulted in protein yields of 20.6% and 15.4%, respectively. Wet lipid extraction of deproteinized biomass resulted in a less stable emulsion that released twice the solvent than the control biomass. However, the faster separation of phases that occurred during the wet lipid extraction of the deproteinized biomass resulted in a lipid yield twice lower than the control biomass.