6-Aminopenicillanic acid production in stationary basket bioreactor with packed bed of immobilized penicillin amidase-Penicillin G mass transfer and consumption rate under internal diffusion limitation

The external and internal mass transfers of Penicillin G in the process of its enzymatic hydrolysis to 6-Aminopenicillanic acid under competitive and non-competitive inhibitions using a bioreactor with stationary basket bed of immobilized penicillin amidase have been analyzed. By means of the Penicillin G mass balance for a single particle of biocatalysts, considering the specific kinetic model proposed by Warburton et al., mathematical expressions have been developed for describing the profiles of Penicillin G concentrations and mass flows in the outer and inner regions of biocatalyst particles, as well as for estimating the influence of internal diffusion on its hydrolysis rate. The results indicated that very low values of internal mass flow could be reached in the particles centre. The corresponding region was considered an "enzymatic inactive region", its extent varying from 0 to 51% from the overall volume of each biocatalyst. By enzyme immobilization and using the basket bed, the rate of enzymatic reaction is reduced over 160 times compared to the process with free enzyme (c) 2012 Elsevier B.V. All rights reserved.