Lipase-catalyzed synthesis of ferulyl oleins in solvent-free medium

Lipase-catalyzed transesterification of ethyl ferulate (EF) with triolein (TO), to form ferulyl oleins in a solvent-free medium, was investigated. Water activity (aw) had an obvious influence on transesterification efficacy. A possible explanation is that the reaction of EF with TO would be deacylation-rate determined. In order to enhance the combined yield of ferulyl diolein (FDO) and ferulyl monoolein (FMO) and minimize hydrolysis of substrate, glycerol (rather than water) was introduced to the reaction. A maximal combined yield of 29.0% of FDO and FMO was obtained using a 1:3 mole ratio of glycerol to TO in solvent-free medium at 60 °C. Compared to the ferulyl olein synthesis conducted by the normal pressure magnetic stirring procedure, the synthesis of ferulyl oleins by a vacuum-rotary evaporation procedure, with a vacuum of 7.5 mmHg, affords higher yields within the same time. The enzyme can be reused several times without significant loss of activity.