Organic solvent-free lipid extraction from wet Aurantiochytrium sp biomass for co-production of biodiesel and value-added products

Increasing demand for renewable energy has led to the production of bio-diesel from microalgae. Microalgae have been regarded as one of the best feedstocks for bio-diesel due to their high growth rate and lipid content as compared to other crops and plants. However, use of microalgae is still hindered by technical barriers and high processing costs. The economic viability and environmentally friendly aspects of bio-diesel production will be significantly improved by co-producing value-added chemicals and extracting lipids directly from wet biomass without involvement of organic solvents, respectively. In this study, organic solvent-free lipid extraction from wet Aurantiochytrium sp. biomass was developed to co-produce biodiesel and value-added products such as docosahexaenoic acid. Organic solvent-free lipid extraction was performed by applying alkali and heat treatments to wet biomass. Key parameters for the extraction from Aurantiochytrium sp. were optimized to increase extraction yields. A ratio of 15 mg/mL of biomass to alkaline solution and an alkaline solution concentration of 1% w/w were determined to be the optimal conditions. Both heating temperature and treatment time were associated with positive effects on lipid recovery, up to a certain level. The maximum extraction yield (77.37% of total lipid) was obtained by heating at 150 degrees C for 30 min. Additionally, microwaves were employed to the extraction system and could further reduce the reaction time. Our study could be expanded to other types of microalgal biomass and will aid in establishing a protocol for organic solvent-free lipid extraction directly from wet biomass.