Production of 6-Aminopenicillanic Acid in Immobilized Enzyme Reactor with Electrodialysis

Abstract

Phenylacetic acid, an inhibitory product, was formed through the hydrolysis of penicillin G by immobilized penicillin acylase. In this study, electrodialysis was applied to remove phenylacetic acid continuously from the reaction mixture and to enhance the efficiency of the reaction. The permeation rate of phenylacetic acid, in this electrodialysis system was found to be much faster than those of two other compounds, penicillin G and 6-aminopenicillanic acid. Therefore, the membranes selected here might be suitable for continuous removal of phenylacetic acid from the reaction mixture for penicillin G hydrolysis. However, the permeation rate of phenylacetic acid was significantly influenced by the penicillin G concentration; it decreased with increasing penicillin G concentration. A theoretical model was developed to describe this phenomenon and was applied to the hydrolysis of penicillin G by means of a combination of immobilized penicillin acylase and electro dialysis. The experimental data were compared to those predicted by a model using independently determined parameters such as the Michaelis constant, inhibition constants and permeation rate constants. Fairly good agreement was found between the theoretical and experimental data. When a 100 mol·m-3 penicillin G solution was used as the substrate, the time required to reach 98 % conversion could be reduced to 24.7 % by using the combination with electrodialysis. © 1993, The Society of Chemical Engineers, Japan. All rights reserved.