Noro_2023_ChemSusChem__e202300615

In this work, three deep eutectic mixtures (DES1: choline chloride:urea; DES2: choline chloride: glycerol; and DES3: tetrabutylammonium bromide:imidazole) were investigated as mediums for the synthesis of glucose laurate and glucose acetate. Aiming to achieve a greener and more sustainable approach, the synthesis reactions were catalyzed by lipases from Aspergillus oryzae (LAO), Candida rugosa (LCR), and porcine pancreas (LPP). The hydrolytic activity of lipases against p-nitrophenyl hexanoate revealed no evidence of enzyme inactivation when DES were used as medium. Regarding the transesterification reactions, combining LAO or LCR with DES 3 resulted in the efficient production of glucose laurate (from glucose and vinyl laurate) (>60%). The best result for LPP was observed in DES 2, with 98% of product production after 24 hours of reaction. When replacing vinyl laurate by a smaller hydrophilic substrate, vinyl acetate, a distinct behavior was observed. LCR and LPP performed better in DES 1, yielding more than 80% of glucose acetate after 48 hours of reaction. The catalytic activity of LAO was less pronounced, reaching only nearly 40% of product in DES 3. The results highlight the potential of combining biocatalysis with greener and environmentally-safer solvents, for the synthesis of differentiated chain-length sugar fatty acid esters (SFAE).