Lutein extraction by imidazolium-based ionic liquid-water mixture from dried and fresh Chlorella sp.

Abstract

Lutein is one of high-value added pigments from microalgae. Several energy-consuming methods for cell wall disruption have been developed due to the rigid cell wall of green algae. Ionic liquid - based approaches are considered as green technology for lutein extraction from microalgae. The structure and components of cell wall of microalgae are species specific so that it is necessary to select a suitable ionic liquid for lutein extraction. Two protocols using imidazolium-based ionic liquid from dried or fresh microalgae were evaluated for increasing the extraction efficiency of lutein from Chlorella sp. In the pretreatment process, [BMIM]Cl, [BMIM]Br, [EMIM]Cl and [EMIM]EtOSO3 were investigated. The concentration of these ionic liquids in aqueous solution, treatment temperature and time, and solid-liquid ratio (dried algae powder: ionic liquid aqueous solution) were also evaluated. The organic solvent and extraction times in lutein extraction process were also assessed. Compared with the protocol 1 (extraction from dried microalgae), extraction from fresh microalgae (protocol 2) had higher final lutein content and similar lutein extraction efficiency. Finally, the extraction efficiency was 97.73% when 10% [BMIM]Br was used to enhance cell disruption under 65 °C for 60 min for fresh microalgae. The solid-liquid ratio was 1:122. Diethyl ether was better than hexane, acetone and ethyl acetate as organic solvent. Seven times of extraction by organic solvent were enough and each time was 80 s. The current result is valuable for further development.