Kinetic Study of Growth and Penicillin G Acylase Production by Escherichia coli

Abstract

Penicillin G acylase (PGA) is one of the most widely used enzymes at an industrial scale. It is used to hydrolyze penicillin G to produce 6-aminopenicillanic acid (6-APA), a required intermediate in the production of semisynthetic penicillins. Escherichia coli is the most abundantly used organism for PGA production. Present study was focused on the kinetics of growth and PGA production of three local E. coli isolates, FH6-NIAB, FMu2-NIAB and FD25-NIAB. Optimal enzyme production was reached after 18 hr. For longer incubations, the enzymatic activity decreased slightly. PGA activity was detectable after about 6 hours of incubation. For the selected isolates, PGA production was determined for various concentrations of glucose and phenylacetic acid in the medium. PGA production by E. coli isolates was completely repressed by glucose concentration above 5 g/l. Production of PGA by E. coli isolates was completely dependent upon the presence of PAA in the medium and optimal enzyme activity was obtained between 1 g/l and 2 g/l of PAA. Enzyme activity was found to be highest when PAA was used as an inducer. PGA production by our local E. coli isolates was completely inducible.