Enzymatic synthesis of fatty eaters Part I. Kinetic approach

A kinetic study of palmitic acid esterification reaction catalyzed by immob ilized lipase Novozym 435 (from Candida antarctica) has been made in a rang e of 65-75 degrees C temperature and 3-7% of initial catalyst concentration and atmospheric pressure, influence of operating variables also was studie d. Different values of temperature, initial lipase concentration, acid/alco hol molar ratio, and products concentrations were tested. Experiments were carried out in a stirred batch reactor equipped with adequate control syste ms. Evolution of concentration of the species involved was found by using g as-liquid chromatography. The kinetic characteristics observed in the ester ification reaction with isopropanol were found to follow an ordered bi-bi m echanism with competitive inhibition by reactants and products. According t o the mechanism maximum reaction rate, Michaelis-Menten constants and inhib ition constants were determined. A good quality of fit was observed by fitt ing experimental rate data to the kinetic model with an average error benea th the 15%. Kinetic constants, as well as enthalpy and entropy values, have been determined for the model proposed for the esterification reaction wit hin the experimental range studied. (C) 1999 Elsevier Science Inc. All righ ts reserved.