A Novel Material for Selective Separation of Monogalactosyldiacylglycerols from Microalgae

Monogalactosyldiacylglycerols (MGDGs) have potential applications in food products, cosmetics and pharmaceuticals. MGDGs from microalgae with high amounts of polyunsaturated fatty acids (PUFAs) have potential functions, which arise the interest of the researchers. MGDGs were prepared by silica gel column chromatography with the appropriate mobile phase, while due to the similarity to molecular structure of MGDGs, digalactosyldiacylglycerols (DGDGs) were the most difficult impurities to separate during the extraction process of MGDGs from Nannochloropsis oceanica IMET1 and Arthrospira platensis. In order to obtain MGDGs from microalgae using low toxic solvent system, a novel material Click thiol-ene cysteine (Click TE-Cys) was employed to achieve its selective separation by differentiation of the hydrophilic interaction. The mixture of MGDGs and DGDGs standards were separated from each other by Click TE-Cys solid phase extraction (SPE), which was further confirmed by the result of LC-MS. The molecular interaction of MGDGs and DGDGs with Click TE-Cys demonstrated that DGDGs had more hydrogen bonds with Click TE-Cys material, which might cause a higher hydrophilic interaction. In this study, the Click TE-Cys material exhibited higher hydrophilicity with DGDGs and effectively separated MGDGs from 4 species microalgae by ‘flow-through’ mode using ethanol as mobile phase.