Selective Extraction of Lutein from Alcohol Treated Chlorella vulgaris by Supercritical CO2

A pretreatment process using alcohol for the removal of chlorophyll a, b and beta-carotene from Chlorella vulgaris was developed to improve the yield and selectivity of lutein in the extract obtained by supercritical carbon dioxide extraction. Supercritical carbon dioxide extraction was carried out after pretreatment in the pressure range of 20 to 40?MPa and the temperature range of 40 to 80?degrees C. Ethanol and methanol were selected as elution solvents, of which ethanol was found most suitable for the elution, or pretreatment, process. The amounts of lutein and other compounds were analyzed by HPLC with the mixture of methanol and THF as the mobile phase. The amount of lutein in the extract increased with pressure, but decreased with extraction temperature. The highest recovery percentage and the selectivity of lutein were around 52.9 +/- 0.02?% and 43.1 +/- 0.02?%, respectively, obtained from supercritical carbon dioxide extraction with pretreatment and ethanol entrainer at 40?MPa and 40?degrees C.