Sonication-assisted homogenization system for improved lipid extraction from Chlorella vulgaris

• Sonication-assisted homogenization system effectively breaks up microalgal cell wall.
• Chloroform-methanol system shows improved lipid extraction efficiency than hexane.
• Dual mechanical approach is a good cell disruption method.

Microalgae, as biodiesel feedstock, are promising renewable energy sources that can be continuously developed into the future. Because recovery of microalgal lipid from dry microalgae incurs high costs, particularly in the dewatering process, wet extraction has been suggested as an attractive alternative approach. In the present study, the feasibility of a sonication-assisted homogenization system for lipid extraction from Chlorella vulgaris was evaluated. To that end, lipid-extraction performance, according to reaction time, cell concentration, and solvent type, was investigated. The initial fatty acid content of the C. vulgaris was 360.2 mg/g cell. The combination of sonication and homogenization broke up the microalgal cell walls, thereby facilitating lipid recovery. By this method, the lipid-recovery yields were increased compared with that by solo use of either homogenization or sonication. Further, chloroform-methanol, as a recovery solvent, significantly enhanced lipid recovery (237.5 mg lipid/g cell at 60 min reaction time) relative to hexane (152.0 mg lipid/g cell at 60 min reaction time).