Novel screening methods - The key to cloning commercially successful biocatalysts

Providing sufficient biocatalyst to support the demands of multi tonne prod uct supply can be problematical. Here we describe how screening for and clo ning a gamma-lactamase overcame biocatalyst supply issues, and greatly impr oved the actual biocatalytic process. The isolation of an expressing gamma- 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 wi th regard to its process performance and proved to be active at 500 g L-1 s ubstrate. Further development of the recombinant fermentation and downstrea m processing has resulted in the ability to produce sufficient biocatalyst from one 5001 fermentation to resolve 5 metric tonnes of (+/-)-lactam, whil st simplifying the process chemistry greatly. (C) 1999 Elsevier Science Ltd . All rights reserved.