ENZYMATIC ESTERIFICATION BY SURFACTANT-COATED LIPASE IN ORGANIC MEDIA

Surfactant-coated lipases have been prepared with a synthesized surfac tant. Preparation conditions to obtain a suitable surfactant-coated li pase were investigated. The enzymatic activity of the lipase in an org anic solvent significantly increased with the coating of the surfactan t. The esterification rate from the surfactant-coated lipase was much higher than that from the powder lipase. An aliphatic solvent showed h igher activity than did alcohol, aromatic, and chloric solvents. Among them, isooctane gave the highest activity. The reactivity of the surf actant-coated lipase depends on the pH of the aqueous solution in the preparation and on the buffer solution. Surfactant-coated lipase prepa red in the middle pH range using phosphate buffer showed high enzymati c activity. The surfactant-coated lipase was thermostable at high temp erature compared to the native lipase. A kinetic study enabled a ping- pong bi-bi reaction mechanism with alcohol inhibition to be suggested. From the kinetic analysis, it was found that an alcohol substrate inh ibits enzymatic esterification by lipase. The reaction rate of the coa ted lipase was about 100 times that of the powder lipase.