Mechanism of deep eutectic solvent-mediated microalgal biomass disintegration for enhanced lutein extraction

Microalgae as a source of natural lutein get increasing attention since they feature a high quantity and quality of this pigment. Recalcitrance of the microalgal cell wall declines the bioaccessibility, bioavailability, and digestibility of the beneficial compounds contained in the microalgae. This study aimed to evaluate the influence of deep eutectic solvent (DES) based approaches for the disintegration of Chlorella pyrenoidosa cells for lutein recovery and explore the underlying mechanism. The results showed that choline chloride-ethylene glycol DES (ChCl:EG 1:2) achieved a better cell disintegration and lutein stability than other DESs. Molecular dynamics simulations revealed that chloride anion (Cl-) dominated the dissolution of cellulose for breaking down cell wall structure of C. pyrenoidosa. Solvent screening and process optimization resulted in 239.92 mg/100 g lutein yield with ethanol solvent under optimized condition. Disintegration significantly increased the release of lutein from microalgae. This study provided the theoretical guidance and experimental prove of improve lutein extraction from microalgal biomass in a green and sustainable extraction procedure.