Applications of immobilized lipases to transesterification and esterification reactions in nonaqueous systems

Lipases from Candida cylindracea, Aspergillus niger, and Pseudomonas fluorescens were immobilized by adsorption on anion-exchange resin and diatomaceous earth using buffer or hexane as a reaction medium. The enzyme preparations were tested in the transesterification of triolein with lauric acid and the esterification of lauric acid with different alcohols. Immobilized C. cylindracea preparations were more active when hexane was used as the reaction medium, and anion-exchange resin was a better support than diatomaceous earth. Hexane was also a better immobilization medium for A. niger lipase. No difference was observed in the lipase activity of P. fluorescens lipase immobilized in different ways. The synthetic activities of the immobilized enzymes could be predicted from their hydrolytic activities: the higher the hydrolytic activity, the higher the synthetic activity. There was no direct correlation, however, between the lipolytic and the transesterification activities.