Effect of mass transfer in a recirculation batch reactor system for immobilized penicillin amidase

Abstract

The effect of external mass transfer resistance on the overall reaction rate of the immobilized whole cell penicillin amidase of E. coli in a recirculation batch reactor was investigated. The internal diffusional resistance was found negligible as indicated by the value of effectiveness factor, 0. 95. The local environmental change in a column due to the pH drop was successfully overcome by employing a buffer solution. The reaction rate was measured by the pH-stat method and was found to follow the simple Michaelis-Menten law at the initial stage of the reaction. The values of the net reaction rate experimentally determined were used to calculate the substrate concentration at the external surface of the catalyst pellet and then to calculate the mass transfer coefficient, k//L, at various flow rates and substrate concentrations.