Factors affecting cellular lipid extraction from marine microalgae

Factors affecting intracellular lipid extraction from marine microalgae were investigated using various techniques. The biomass drying method and moisture content, and the solvent extraction system were the factors studied. Lipid was analytically classified into three categories i.e. neutral lipid, free fatty acid (FFA) and polar lipid using solid-phase extraction. Biomass drying methods (freeze-, oven- and solar drying) did not affect lipid yield, but the FFA content of the lipid was three times higher for solar dried biomass. Of the various lipid extraction methods tested, including sonication, homogenization, accelerated solvent extraction (ASE) and Soxhlet extraction, sonication was the least efficient compared to other methods when a partially miscible solvent system i.e. hexane–methanol was used. Chloroform–methanol solvent system had maximum lipid extraction efficiency (33%). A biomass moisture content up to 5% had no impact on lipid extraction efficiency, but higher moisture contents reduced lipid extraction and increased the FFA fraction.

• Investigate key factors affecting extraction efficiency and lipid characteristics.
• FFA was increased 3 times in extracted lipid for microalgae dried by solar.
• Chlorinated solvent systems resulted in higher extraction efficiencies than other solvent.
• Hexane had a poor extraction efficiency, but improved when polar solvents were added.
• The moisture content affected both lipid extraction efficiency and FFA content.