Continuous production of 6-amino penicillanic acid (6-APA) by agarose immobilized penicillin acylase in a packed column reactor

Abstract

Penicillin acylase, an industrially important biocatalyst catalyzes the conversion of penicillins to 6-amino penicillanic acid (6-APA) which is the main precursor for the production of semi-synthetic β-lactam antibiotics. The present work involves the continuous production of 6-APA in a packed column reactor by using agarose immobilized penicillin acylase as a block polymer. The strain Escherichia coli ATCC 11105 was used as enzyme source and penicillin G as substrate. The acidic nature of 6-APA has an inhibitory effect on the enzyme and so the continuous system of production is a better choice. To overcome this problem, penicillin acylase was physically entrapped on agarose gel. Kinetic quantities ζmax and Km values were calculated for both native and immobilized enzyme. The immobilized enzyme was packed in the column reactor to study the maximum capacity of the reactor in diffusion free condition by varying flow rate and different substrate mass fraction. F max value was calculated using secondary plot of 1/F vs. 1/Q to find the maximum capacity of the bioreactor according to the model of Lilly et al. 1966. This study is very useful and applicable to the industry for the conversion of Penicillin G to 6-APA.