Selenastrum Capricornutum: Harvesting and Oil Extraction, for Biodiesel Production
An alternative for biodiesel production is the use of lipids from microalgae. Although all steps to obtain this biofuel are important, harvesting and extraction are the most important. Advances in these areas are necessary in order to obtain third-generation fuels. The purpose of the present study is to compare different methods of lipids extraction and harvesting for freshwater Selenastrum Capricornutum microalgae. The method used for harvesting was flocculation with inorganic agent. Copper (II) Sulphate (CuSO4) was used as flocculant, resulting in the best percentage of recovery (76%) for a dose of 2 g/L. Previously oil extraction, the collected samples were homogenized and their moisture content was analysed obtaining values of 55-96%. Two extraction methods were used: Soxhlet and ultrasound. The use of ultrasound favours cell disruption and increases the extraction yield. In extraction methods, polar, non-polar solvents, and mixes of solvents were used. N-hexane and acetone were used as solvents for Soxhlet extraction, and ethanol, acetone, methanol, chloroform, and a mixture of chloroform and methanol in 1:2 and 2:1 ratios, for extraction ultrasound assisted method. The use of the methanol-assisted ultrasound is the most efficient method for lipids extraction for Selenastrum Capricornutum biomass.
Keywords: microalgae, extraction, ultrasound, Soxhlet, solvent, harvesting