Kinetic Model for Removal of Phenol by Horseradish Peroxidase with PEG

Abstract

A kinetic model has been developed to simulate horseradish peroxidase-catalyzed polymerization of phenol in the presence of polyethylene glycol based on the following kinetics. The phenol conversion expression is a second-order Michaelis–Menten equation with respect to the concentrations of phenol and hydrogen peroxide. The enzyme inactivation is attributed to the polymer and hydrogen peroxide simultaneously. The inactivation by polymer is an apparently second-order reaction, first-order in each of enzyme and phenol, whereas the inactivation by peroxide is also an apparently second-order reaction, first-order in each of enzyme and hydrogen peroxide. The rates of consumption of hydrogen peroxide and polyethylene glycol are directly proportional to the rate of conversion of phenol. Experimental data show that the model output can predict the phenol removal and activity depletion realistically under a variety of reaction conditions. The model has been verified by predicting some independent experimental results on reaction stoichiometry, horseradish peroxidase dose effect, and semibatch operation with respect to hydrogen peroxide.