Kinetic model for the esterification of oleic acid and cetyl alcohol using an immobilized lipase as catalyst

A kinetic model has been developed for the enzymatic esterification of oleic acid with cetyl alcohol catalyzed by a Candida antarctica immobilized lipase. The model is based on an ordered reaction mechanism with two reactants and two products. The reaction mechanism includes two groups of steps. The first group consists of reaction steps, while the second is formed by the inhibition steps involving enzymatic complexes or free lipase. The reaction has been carried out at a laboratory scale in a stirred tank reactor. The operating conditions have been fixed so that the system operates in liquid phase and can be considered as pseudohomogeneous with regard to the how conditions. Depending on the pressure level, the reaction can be considered reversible or irreversible. In both cases the kinetic model has been proposed to cover a range of temperatures between 70 and 80 degrees C, an initial concentration of immobilized lipase between 3 and 7 wt%, and considering different molar ratios of reactants. Parameter estimation was carried out by using computer programmes based on numerical calculation algorithms. Discrimination of parameters was carried out by considering their physical meaning and the adequate prediction of the experimental results. Finally, the validity of the proposed models was quantified by means of residual analysis and simulation experiments. (C) 2000 Elsevier Science Ltd. All rights reserved.