With only few exceptions, cephalosporins derivatives are obtained from the same key intermediate 7-amino-cephalosporanic acid (7-ACA, 3).

This intermediate is chemically produced from cephalosporin C (1) in about 1770 tpa scale. However, the chemical process has several drawbacks related to the use of aggressive reagents (with the consequent disposal of toxic byproducts in the waste waters) as well as to the need of working at low temperatures.

As an alternative, 3 can be produced biocatalitycally using the two-step enzymatic process depicted in the following Scheme:

A batch of immobilized glutaryl-7-ACA acylase (GA), prepared for plant-scale industrial production, has been characterized, describing the dependence of the biocatalyst activity and stability on buffer concentration, pH and temperature. Moreover, the residual enzymatic activity after incubation in the presence of different amounts of H₂O₂, a side-product of the reaction catalyzed by the D-amino acid oxidase (DAAO), was evaluated.

Operational stability of the immobilized GA was determined carrying out the bioconversion of glutaryl-7-ACA (2) to 7-ACA (3) under operative conditions. The catalyst was recovered after each conversion cycle and used again, and enzyme activity was measured monitoring the reaction by analytical HPLC.

The bioconversion was repeated for 16 cycles and, at the end, approximately 89 % of the initial enzymatic activity was retained.