Microemulsions as vehicles for lipase catalyzed reactions

Abstract

Microemulsions have proved to be excellent reaction media for several types of enzymatic lipid trnasformations. Using a 1,3-specific lipase transesterification, selective hydrolysis and glycerolysis reactions have been performed in good yield with a high degree of regioselectivity. The rate of transesterification was found to be highly dependent on the type of unsaturation of the fatty acid residues; a double bond in the 6-position, as in γ-linolenic acid, inhibited the reaction. — All reactions were made in microemulsion containing 0.572-5% water. Attempts were made to perform glycerolysis in a water-free microemulsion with glycerol as the polar component. The rate of reaction was very low, however, in the absence of water. — the reactions were governed by the choice of surfactant of the microemulsions. Nonionic surfactants were found to be unsuitable for the hydrolysis reactions, giving slow reaction rates and low yields. These surfactants probably form a plalisade layer at the interface which prevents the enzyme access to the organic domains in which the substrate is located.