Industrial landmarks in the development of sustainable production processes for the β-lactam antibiotic key intermediate 7-aminocephalosporanic acid (7-ACA)

Reflecting its importance as key intermediate for the large scale manufacture of β-lactam-type antibiotic drugs being widely used in antibacterial therapy, tremendous achievements have been made over the past decades in developing both, economically and ecologically attractive production routes for 7-aminocephalosporanic acid (7-ACA). Representative achievements and industrial landmarks thereof are described in this review. With cephalosporin C a starting material being accessible through fermentation is readily available in bulk quantities. Initially a chemical production process in organic medium based on various reagents for protection group chemistry and acyclic amide activation served as the large scale production technology for transforming cephalosporin C into 7-ACA. Subsequently, a bi-enzymatic production in aqueous reaction medium based on the use of a D-amino acid oxidase for side chain modification and glutaryl acylase for side chain cleavage was developed. This biocatalytic approach also turned out as an industrial scale solution and dramatically reduced the amount of waste from 31 kg (for the "original chemical process") to less than 1 kg. The latest innovation has been the extension of the two-step bi-enzymatic process towards a one-step monoenzymatic process based on a direct cleavage of the acyclic amide bond of cephalosporin C by means of a cephalosporin C acylase. This alternative, economically efficient and sustainable biotechnological process has already been established on industrial scale in recent years. These biotechnological achievements represent industrial landmarks in biocatalysis and examples that modern biocatalysis can contribute to the development and implementation of highly economical as well as sustainable industrial manufacturing processes.

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