AN EXTENSION OF THE HARANO-OOSHIMA RATE EXPRESSION FOR ENZYMATIC-HYDROLYSIS OF CELLULOSE TO ACCOUNT FOR CHANGES IN THE AMOUNT OF ADSORBED CELLULASE

Three empirical rate expressions, Kinetics I, II, and III, for the enz ymatic hydrolysis of cellulose were evaluated in an effort to develop a easy-to-use rate expression. They are based on the following equatio n: -dV/dX = kV, where V and X are the hydrolysis rate and the fraction al conversion. In Kinetic I, k is constant. In Kinetic II, a linear re latinship between k and t is assumed. In Kinetic III, an exponential r elationship is assumed. The three expressions were applied to enzymati c matic hydrolysis carried out under seven different conditions in whi ch the kinds of substrates, enzymes, and initial concentrations were v aried. All of the examined rate expressions were applied to the hydrol ysis with success, but the better accuracies were obtained by Kinetic III, Kinetic II, and Kinetic I in this order. The variations of k with time found in this study, especially the exponential relationship, we re consistent with the effect of the measured changes in the concentra tion of adsorbed enzyme as predicted by theory developed previously by Ooshima et al. (1).