LIPASE PS-CATALYZED TRANSESTERIFICATION OF CITRONELLYL BUTYRATE AND GERANYL CAPROATE - EFFECT OF REACTION PARAMETERS

Pseudomonas sp. lipase PS was immobilized by adsorption and tested for its ability to catalyze the synthesis of citronellyl butyrate and ger anyl caproate by transesterification in n-hexane. The reaction paramet ers investigated were: enzyme load, effect of substrate concentration, added water, temperature, rime course, organic solvent, pH memory, an d enzyme reuse. Yields as high as 96 and 99% were obtained for citrone llyl butyrate and geranyl caproate, respectively, with 300 units (appr ox. 15% w/w of reactants) of lipase PS. Increasing amounts of terpene alcohol inhibited lipase activity, while excess acyl donor (triacylgly cerol) concentration enhanced ester production. Optimal yields were ob tained at temperatures from 30-50 degrees C after 24-h incubation time . Yields of 90 and 99% were obtained for citronellyl and geranyl ester s, respectively, with 2% added water. Solvents with log P values great er than or equal to 2.5 showed the highest conversion yields. pH 7 and 6-8 seemed to be ideal for citronellyl butyrate and geraniol caproate , respectively. The lipase remained active after reusing 12 times.