Process Optimization of Lipid Extraction from Microalgae Aphanothece halophytica in Wet and Dry Conditions

Unearthing new sustainable and economically viable sources for biofuel production which do not affect the environment is a dire need of the hour. Microalgae is one such promising source due to its high lipid content, productivity, and carbon neutrality. Identification of appropriate strain and process optimization decides the biomass productivity, nutrient value, and oil content which are the major factors for commercialization. In the present work, mass cultivation of halophilic Aphanothece halophytica in raceway ponds was optimized by using organic and inorganic nutrients by using design of experiments. Organic flocculant, neem plus was successfully adapted for harvesting the biomass and oil extraction was done with solvent methodology. A maximum lipid yield of 29.3% was obtained on wet basis, when the reaction temperature, reaction time, biomass-to-solvent ratio and mixing intensity were kept at 68 ºC, 190 min, 9:1, and 300 rpm respectively. Similarly, on dry basis, a lipid yield of 27.5% was reported when the reaction temperature, reaction time, biomass-to-solvent ratio and mixing intensity were maintained at 68 ºC, 190 min, 12:1, and 300 rpm respectively. GC–MS analysis of the lipid was done to appropriate the combination of fatty acid for enhancing the biofuel production.