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. © 1974 Academic Press Inc.
Vandamme, E. J., & Voets, J. P. (1974). Microbial Penicillin Acylases. Advances in Applied Microbiology, 17(C), 311–369. https://doi.org/10.1016/S0065-2164(08)70563-X