Improved enzymatic galactose oleate ester synthesis in ionic liquids

A fast and improved lipase-catalyzed synthesis of galactose oleate ester was performed in 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) ionic liquid with the addition of dimethylsulfoxide (DMSO) as a solubilizing agent and co-solvent; and Lipozyme RM IM (lipase from Rhizomucor miehei immobilized on macroporous anion exchange resin) as the biocatalyst. Different reaction parameters (type of solvent, type of enzyme, amount of enzyme, reaction time, temperature, stirring rate and substrate molar ratio) were studied. A high conversion (87%) was obtained after only 2 h at optimal synthesis conditions (1:20 DMSO:[Bmim][BF4] ratio with 2% (w/w) Lipozyme RM IM, temperature 60 °C, stirring rate of 300 rpm and a molar ratio of galactose to oleic acid of 1:3).