Kinetic analysis of enzymatic esterification of fatty acids and ethanol

Abstract

The esterification of oleic acid and ethanol with immobilised lipase in a solvent-free media is presented in this work. The reaction has been carried out at a laboratory scale in a stirred tank reactor operating batchwise. The evolution of oleic acid conversion to ester was determined by using two analysis techniques: measurement of the acid index and gas chromatography. The influence of the operating conditions on the equilibrium conversion and conversion-time profiles was analysed. The amount of enzyme, temperature, initial alcohol/oleic acid molar ratio and initial water content were considered. A kinetic model has been developed for the enzymatic esterification of oleic acid and ethanol catalysed by Candida Antartica immobilised lipase. Some kinetic models were considered and a second order reaction kinetic was selected. The parameter adjustment was carried out by using a computer program based on Marquardt algorithms. The results from the simulated experiments by using the proposed model showed a satisfactory agreement with the experimental data.