ENZYMATIC-SYNTHESIS OF GERANYL ACETATE BY TRANSESTERIFICATION WITH ACETIC-ANHYDRIDE AS ACYL DONOR

Pseudomonas sp. lipase (PS) was immobilized by adsorption technique on to glass beads and tested for its ability to synthesize geranyl acetat e by transesterification with acetic anhydride as the acyl donor. Reac tions were carried out in n-hexane containing 0.1 M geraniol, 0.1 M ac etic anhydride, and 200 units of lipase PS. Enzyme load, effect of sub strate concentration, added water, temperature, time course, organic s ol vent, pH memory, and enzyme reuse were studied. Yields of up to 96% were obtained with 200 units (approximately 11% w/w of reactants) of enzyme. Increasing amounts of geraniol inhibited lipase activity, whil e excess acyl donor concentration enhanced ester production. Yields as high as 97% were obtained at 50 degrees C, 24 h incubation, with no a dded water. Solvents with log P values greater than or equal to 3.0 sh owed the highest conversion yields. Solvent-free samples also performe d well. The pH range of 4-9 gave good yields (92-98.4%). Enzyme reuse studies showed the lipase remained active after 15 runs.