Supercritical fluid extraction of lutein from Scenedesmus cultured in an autotrophical photobioreactor

Lutein is a known health food supplement which is mainly extracted from marigold through the conventional solvent extraction route. The results of lutein recovery by the supercritical fluid extraction (SFE) of CO2 from Scenedesmus powder are reported here. The collected Scenedesmus biomass is cultured in an inner-illuminated photobioreactor at a light intensity of 350–400 μmol/m2 s. The increase of pressure and temperature in the SFE operation enhances the lutein recovery yield. However, the enhancement resulting from the increase of temperature and pressure is not significant as compared to the yield from the conventional methanol extraction method. In addition, the increase of temperature leads to the increased impurity observed in the HPLC profile. To further enhance the lutein recovery yield, the addition of a co-solvent in SFE is performed. Of the five solvent powders investigated, ethanol is regarded as the optimum co-solvent for use in lutein extraction. The optimum amount of ethanol to be added in the SFE operation is determined. The best lutein recovery yield obtained in this study of SFE operation was 76.7% (compared to the conventional methanol extraction method) under the conditions of 400 bar, 70 °C and ethanol as the co-solvent at a ratio of 30 mol%.

► Investigated the application of supercritical CO2 to extract lutein from Scenedesmus powders. ► Discover a SFE method to replace the conventional extraction method for the recovery process of lutein from Scenedesmus powders. ► Temperature and pressure on lutein recovery were examined. ► The best lutein recovery yield obtained in this study of SFE operation was 76.7% (compared to the conventional methanol extraction method) under the conditions of 400 bar, 70 °C and ethanol as the co-solvent at a ratio of 30 mol%.