Extraction of lipids from microalgae by ultrasound application: Prospection of the optimal extraction method

Microalgae have the ability to grow rapidly, synthesize and accumulate large amounts (approximately 20–50% of dry weight) of lipids. A successful and economically viable algae based oil industry will depend on the selection of appropriate microalgal strains and the selection of the most suitable lipid extraction method. In this paper, five extraction methods were evaluated regarding the extraction of lipids from Chlorella vulgaris: Bligh and Dyer, Chen, Folch, Hara and Radin, and Soxhlet. Furthermore, the addition of silica powder was studied to evaluate the introduction of more shear stress to the system as to increase the disruption of cell walls. Among the studied methods, the Bligh and Dyer method assisted by ultrasound resulted in the highest extraction of oil from C. vulgaris (52.5% w/w). Addition of powder silica did not improve the extraction of oil.

► Bligh and Dyer method assisted by ultrasound resulted in the highest extraction of oil.
► Addition of powder silica did not improve the extraction of oil.
► Diffusion mechanism was more important than cell rupture during extraction.
► Polar solvent systems improve the extraction of microalgae oil.