Extraction of squalene from yeast by supercritical carbon dioxide

Squalene produced under anaerobic conditions, by a strain of Torulaspora delbrueckii was extracted from the biomass using supercritical carbon dioxide. Minimum use of solvent, lower time of isolation and a higher selectivity of extraction merit use of supercritical fluid extraction (SFE) technique over solvent extraction of squalene, as optimized and reported previously. A maximum squalene yield of 11.12 mug g(-1) (dry weight) of yeast cells was obtained at a temperature of 60 degreesC and pressure of 250 - 255 bar at a constant flow rate of 0.2 l min(-1) of carbon dioxide. Lyophilization prior to SFE increased the squalene yield to 430.52 mug g(-1) dry weight of yeast cells, an amount that is far greater than that obtained by ( 2: 1) chloroform - methanol solvent extraction.