Novel screening methods--the key to cloning commercially successful biocatalysts.

Abstract Providing sufficient biocatalyst to support the demands of multi tonne product supply can be problematical. Here we describe how screening for and cloning a γ-lactamase overcame biocatalyst supply issues, and greatly improved the actual biocatalytic process. The isolation of an expressing γ-lactamase clone from a gene library necessitated a combination of classical molecular biology techniques together with innovative screening methods to identify a functional clone. Once isolated the enzyme was characterised with regard to its process performance and proved to be active at 500 g L −1 substrate. Further development of the recombinant fermentation and downstream processing has resulted in the ability to produce sufficient biocatalyst from one 500 l fermentation to resolve 5 metric tonnes of (±)-lactam, whilst simplifying the process chemistry greatly.