Stable biocatalysts of penicillin acylase as gel aggregates and the process of manufacture thereof

A process for preparing a stable and viable biocatalyst;

• wherein said process comprises:
• (a) preparing Cross Linked Enzyme Aggregates from an enzyme by either:
• i) simultaneously precipitating the enzyme from a solution and cross-linking the enzyme with ammonium sulphate and glutaraldehyde at a temperature of between 0° C. and 2° C.;
• or
• ii) cross-linking the enzyme with ammonium sulphate and glutaraldehyde at a temperature of between 18° C. and 23° C. to obtain a self immobilized cross linked enzyme aggregate;
• (b) entrapping the Cross Linked Enzyme Aggregates in a solution of 10% w/w polyvinyl alcohol and 10% w/w gelatin at a temperature of 5° C.;
• (c) maintaining said solution of 10% w/w polyvinyl alcohol and 10% w/w gelatin at a temperature of 5° C. for 12 hours to obtain a gelled solution;
• (d) comminuting said gelled solution to produce gel aggregates having a particle size of between 100 and 300 microns;
• and
• (e) recrosslinking the gel aggregates with glutaraldehyde at 30° C. at a pH of between 7.5 and 7.6 to improve structural stability, thereby obtaining said biocatalyst as a product.