Evaluating Cell Disruption Strategies for Aqueous Lipid Extraction from Oleaginous Scenedesmus obliquus at High Solid Loadings

Among various renewable energy sources, the production of biofuels derived from algal lipids holds bright prospects. One of the major roadblocks in the successful commercialization of microalgal biofuels is the existing energy‐intensive lipid extraction. In the present investigation, an attempt is made to assess aqueous lipid extraction strategies from oleaginous Scenedesmus obliquus at a high solid loading of 15% (w/v). In this study, four surfactants and five enzymes are evaluated for cell disruption of S. obliquus. It is the first report citing cetyl pyridinium bromide as the most suitable cationic detergent for surfactant‐assisted extraction, with a lipid recovery as high as 31.4%. However, during the evaluation of enzyme‐based cell disruption, neutral protease emerges as the best biocatalyst resulting in a lipid recovery of ≈75%. Total lipid extraction is accomplished using a two solvent system comprising of water‐immiscible ethyl acetate, followed by chloroform addition. The study revalidates the fact that the biochemical composition of Scenedesmus sp. plays a vital role while identifying and formulating an efficient and green process for microalgal cell disruption for enhanced lipid extraction under aqueous conditions. Practical Applications: The results of the present study demonstrate that if the biochemical composition of any oleaginous algal cell wall is known, aqueous enzymatic lipid extraction can be employed rather than taking up the conventional route of drying followed by Soxhlet extraction. The combination of using the cheap sources of enzymes and water‐immiscible green solvents like ethyl acetate can be lucrative downstream procedures for the lipid recovery from wet algal biomass when compared to traditional procedures. This study describes an evaluation of cell disruption strategies using environmentally‐benign surfactants and enzymes to extract lipid from oleaginous microalgae Scenedesmus obliquus at a high solid loading of 15% (w/v).