Investigation of the effects of microalgal cell concentration and electroporation, microwave and ultrasonication on lipid extraction efficiency

This study investigated the effects of Chlorella vulgaris (C. vulgaris) concentrations and pretreatment methods, electroporation, ultrasonication, and microwave, on lipids extraction. The C. vulgaris concentrations were varied in the range of 8.4-28.8% for chloroform/methanol/water solvent system and in the range of 7.6-32.0% for n-hexane/methanol/water solvent system. A maximum total lipid yield of 0.248 g/g of dry C. vulgaris was achieved at biomass concentration of about 15% for the chloroform/methanol/water system. This is the highest yield reported for lipids extracted without pretreatment. On the other hand, a maximum lipids yield of 0.139 g/g of dry C. vulgaris was obtained at about 24% biomass concentration for the n-hexane/methanol/water system. When pretreated with electroporation, ultrasonication, and microwave, the yield for lipid extraction increased by 5.3, 26.4, and 28.9%, respectively. Although electroporation resulted in the least amount of yield, it was the most efficient in terms of energy gain per energy input.