Biochemistry and Biotechnology
Wiley InterScience Backfile Collection 1832-2000
Process Engineering, Biotechnology, Nutrition Technology
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, cA0 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 cA0 〈150mM 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, Keq, 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.
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