Preparation of cross-linked enzyme aggregates by using bovine serum albumin as a proteic feeder.

Penicillin G acylase is a major industrial biocatalyst that is used in the enzymatic production of 20,000 t a−1 of 6-aminopenicillanic acid, the industrial β-lactam intermediate, as well as in the enzymatic production of semi-synthetic β-lactam antibiotics. Because efficient recovery and reuse of the biocatalyst is a prerequisite for a viable process, much attention has been focused on the immobilization of penicillin G acylase. Methods that have been studied and will be discussed in this review include covalent attachment to porous organic and inorganic carriers, inclusion in and attachment to biopolymer gels and carrier-free immobilization techniques. Highly active and stable preparations have been developed; mass transfer limitations in the carrier are now a major barrier to further improvement of the biocatalyst performance.

Immobilization of Penicillin G Acylase: The Key to Optimum Performance

Bioconversions in aqueous two-phase systems.

Advances in enzymatic transformation of penicillins to 6-aminopenicillanic acid (6-APA).

Publisher Summary This chapter describes the process of microbial transformation of antibiotics into useful compounds, which is mostly concentrated upon the production of 6-aminopenicillanic acid (6-APA) by enzymatic hydrolysis of biosynthetic penicillins. The chapter describes biotransformation processes of penicillins into 6-APA that use, as a source of acylase, intact bacterial cells, fungal mycelium, fungal spores, crude cell extracts, purified enzyme preparations, stabilized enzymes, and supernatant liquid of extracellular acylase-producing microorganisms. The chapter examines methods to isolate and purify penicillin acylases and to stabilize these enzyme preparations. It reviews the physicochemical properties and the degradation reactions in relation to the structure of penicillins and describes the reaction of cysteine and related compounds with penicillins, resulting in a loss of antibacterial activity. 6-APA was originally produced by fermentation synthesized in a purely chemical way. Enzymatic transformation of biosynthetic penicillins into 6-APA is an industrial process of economic importance as the main source of 6-APA used in the preparation of semisynthetic penicillins.

K. Balasingham

Papers

The isolation and kinetics of penicillin amidase from Escherichia coli

The preparation and kinetics of immobilised penicillin amidase from Escherichia coli.