Polyol based deep eutectic solvent-assisted pretreatment for enhanced lutein extraction from Chlorella pyrenoidosa

The intention of the present study was to develop a green and sustainable extraction procedure to obtain lutein from microalgae. A series of acidic and polyol based deep eutectic solvents (DESs) were synthesized to establish a novel pretreatment process. Response surface methodology (RSM) was adopted to analyzese the significance of pretreatment parameters with high prediction levels of lutein yield. Amongst all the DESs-assisted pretreatment, polyol based ChCl:Gly (1:2) DES obtained the maximum lutein yield at the following optimal conditions: biomass-to-DES ratio, 3:34.6; temperature, 26 °C; time, 40 min. Lutein extraction was optimized by one-factor-at-a-time approach, and results showed that 1.35 mg/g lutein could obtained at 40 °C for 20 min with a biomass-to-solvent ratio of 30 mg/mL. The recyclability of the DES ChCl:Gly (1:2) was also tested and showed satisfactory results up to three cycles. The mechanism of lutein extraction using ethyl acetate was explored by molecular dynamics.