Cross-linked Enzyme Aggregates: Current Developments and Applications

Abstract

Enhanced performance of enzyme is the major challenge which restricts their applications in industrial processes. Different strategies have been proposed to increase their lifetime/performance, they are (1) isolation of novel enzymes which can function under extreme conditions, (2) modifications of enzyme structure to increase their resistance i.e. protein engineering and (3) modification of the solvent environment. However, immobilization, an old technique is still considered as a very powerful tool to improve enzyme properties. In this review, we are presenting a detailed discourse of cross-linked enzyme aggregate (CLEA), as a new method of immobilization. CLEA technology involves precipitation of enzymes using organic solvents followed by cross-linking the precipitated enzymes using a crosslinker. Several additives like starch, bovine serum albumin and polyamines are used to provide additional cross-linking sites for better stability. An appropriate precipitant is required for CLEA formation for a selected enzyme, therefore screening of precipitant is needed which depends on the nature of the enzymes. Optimization of organic solvents, cross-linking concentration and incubation time is a must for optimum performance of CLEA. It shows high stability, reusability and acts as a better catalyst in terms of performance. Furthermore, this technology can be used for the preparation of combi-CLEA using two or more enzymes. It can be a great tool for stabilizing enzymes to improve their overall performance which can be exploited in industries for chemical transformations.