Efficacy of drying and cell disruption techniques on lipid recovery from microalgae for biodiesel production

Downstream processing of microalgal biomass presents a significant challenge to large scale biodiesel production. Scenedesmus sp. which is known to be a potential feedstock for biodiesel production was cultivated in an open circular pond. The biomass productivity peaked at day 21 with a yield of 1.16 g L−1. Biomass was harvested by gravitational settling followed by centrifugation. Harvested biomass was dried using the freeze drying, oven drying and sun drying processes followed by lipid extraction which yielded 29.65%, 28.63% and 28.33% lipid g−1 DCW (dry cell weight) respectively. Lipids were extracted from microalgal biomass dried by selected drying techniques using microwave and sonication for cell disruption in the presence of mixture of chloroform and ethanol (1:1). Microwave assisted extraction of sun dried biomass yielded 28.33% lipid g−1 DCW, as compared to 18.9% lipid g−1 DCW achieved by sonication assisted extraction. The saponification and acid values of the lipid obtained from Scenedesmus sp. dried by selected drying techniques showed high saponification and acid value indicating presence of high free fatty acid content. Effect of different drying and cell disruption technique on fatty acid profile of lipids extracted from Scenedesmus sp. biomass was also studied. These values indicate promising potential of the oil produced for conversion into biodiesel.