The kinetics of penicillin-V deacylation on an immobilized enzyme.

An immobilized Penicillin-V-acylase (commercial name, Novozym 217) with high specificity for the phenoxyacetyl-(V)- side chain was investigated in a recycle reactor and in a batch reactor to find the enzymatic reaction rate as a function of conversion, x, substrate concentration, c(A) (0) and pH. The reaction rate depends strongly on pH, and both products, phenoxy-acetic acid and 6-APA, inhibit the reaction. Nonspecific side reactions amount to only a few per cent when c(A) (0) <150 mM and pH& gt; 6.5. The effectiveness factor for commercial-size particles is found to be about 0.65, and a value of 1.3mM is obtained for the equilibrium constant, K(eq), of the deacylation reaction. A kinetic model for the deacylation process which includes the effect of pH and of the reverse (acylation) reaction is proposed. Rate data for particles of different size are fitted to the nonlinear model. Five kinetic parameters and an effective diffusivity for the immobilized enzyme particles are determined.