ENZYMATIC ESTERIFICATION BY SURFACTANT-COATED LIPASE IN ORGANIC MEDIA

Surfactant-coated lipases have been prepared with a synthesized surfactant. Preparation conditions to obtain a suitable surfactant-coated lipase were investigated. The enzymatic activity of the lipase in an organic solvent significantly increased with the coating of the surfactant. The esterification rate from the surfactant-coated lipase was much higher than that from the powder lipase. An aliphatic solvent showed higher activity than did alcohol, aromatic, and chloric solvents. Among them, isooctane gave the highest activity. The reactivity of the surfactant-coated lipase depends on the pH of the aqueous solution in the preparation and on the buffer solution. Surfactant-coated lipase prepared in the middle pH range using phosphate buffer showed high enzymatic activity. The surfactant-coated lipase was thermostable at high temperature 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 inhibits enzymatic esterification by lipase. The reaction rate of the coated lipase was about 100 times that of the powder lipase.