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 μg g−1 (dry weight) of yeast cells was obtained at a temperature of 60 °C and pressure of 250–255 bar at a constant flow rate of 0.2l min−1 of carbon dioxide. Lyophilization prior to SFE increased the squalene yield to 430.52 μg g−1 dry weight of yeast cells, an amount that is far greater than that obtained by (2:1) chloroform–methanol solvent extraction.