Study of glucose ester synthesis by immobilized lipase from Candida sp.

A simple kinetic model derived from a Ping-Pong mechanism is proposed to describe the mono-esterification of glucose with stearic acid catalyzed by immobilized lipases from Candida sp. The mathematical expressions derived from this model have been tested with several sets of data obtained from reactions carried out at the different reactive temperatures. The predicted values provide very good fits of the experimental data for reactive temperatures from 35 to 45 degrees C, and the rate constants of the corresponding mechanistic reaction are obtained. The activation energy 19.4 kJ/mol is estimated for the formation of the monoester. The model also considers the kinetics of inactivation of the immobilized Candida sp. during the reaction. Reactive condition with 0.8 g molecular sieves/2 mL acetone at 35 or 40 degrees C for 48 h is good for the enzyme to keep its activity and for making the equilibrium produce glucose monoester of stearic acid. (C) 2007 Elsevier B.V. All rights reserved.