Choricystis minor var. minor lipids: Extraction using conventional and pressurized solvents and assessment of their potential to produce fatty acid methyl esters

Microalgae are potential raw materials for biofuel applications. In this work, microbial lipids from Choricystis minor var. minor were extracted with conventional solvents in a Soxhlet apparatus and with compressed fluids with or without the use of a co-solvent (ethanol or hexane). Also, the total achievable yield of fatty acid methyl esters (FAME) was determined in both unextracted microalga, extraction residue and extracted lipids. Ethanol was the best solvent for conventional extraction but hexane was more selective for saponifiable lipids. Compressed propane was better than supercritical carbon dioxide (scCO(2)) for the extraction of microbial lipids and the use of ethanol as co-solvent improved both extraction rates and yields. The best FAME yield was achieved with scCO(2) plus ethanol at 80 degrees C and 150 bar (FAME yield of 16.7 g 100 g(-1) dry biomass for a mass extraction yield of 31.6%). Hexane was not advantageous as an extraction co-solvent.