Enzymatic esterification of free fatty acids in vegetable oils utilizing different immobilized lipases

Different immobilized lipases were screened for their ability to esterify free fatty acids (FFA) with monoacylglycerol (MAG) as acyl-group acceptor. A lipase from Rhizomucor miehei (Lipozyme RMIM) was the most suitable for lipase-catalyzed de-acidification—a promising alternative to conventional neutralization. A reduction of the FFA content to 0.6 % (w/w) was achieved by applying a substrate with an initial FFA-content of 6 % (w/w), the reaction at 50 °C for 22 h as well as the stepwise addition of a quadruple stoichiometric amount of MAG.