Enzymes are biological catalysts which initiate and accelerate biochemical reactions in the living cells. They are proteinaceous in nature and can be extracted from living tissues. They are purified and crystallized. The purified enzyme can carry out a specific biochemical reaction outside the cell. This property of the enzyme has been exploited in it’s use in the area of biotechnology. The enzymes are also modified through enzyme modeling and can be used for gene manipulations. The enzymes are purified by following three steps: dialysis, centrifugation and electrophoresis. The commercially prepared enzymes are purified and then concentrated and sterile filtered. This reduces the volume and the microbial contamination of the sample enzyme. Often, before storage and transport, the sample are freeze dried with additives as sugar substrates and dextrans.

The enzymes are being used commercially and in Industries. In textile Industry, ‘Amylases’ are extracted from bacteria, fungi etc and used as softening agents for starched clothes. Proteolytic enzyme ‘alcalase’ is added in many detergents to remove proteinaceous stains from the clothes. Enzymes isolated from certain bacteria are used commercially to produce acetone, butanol, lactic acid, citric acid etc. In meat and beer processing, the proteases ‘Papain’ (from papaya) and bromelain (from pineapple) are used to tenderize meat. These enzymes hydrolyze the peptide bonds. Similarly a number of enzymes like, 'Glucose isomerase’ in soft drink industry,'‘lactase' in ice-cream industry, 'pectinases' in juice and wine processing etc are being commercially produced and widely used.

Using biotechnology, especially the technique of immobilized enzyme systems, it was possible to produce a variety of substances e.g. high-fructose corn syrup was produced using immobilized enzyme glucose isomerase.
These immobilized enzymes are worth billions of dollars in the market and support multibillion dollar industries. It is especially a profitable venture because the cost involved in the production of these enzymes is only a fraction of the value of the products manufactured.

Immobilization of enzymes is the imprisonment of a biocatalyst in a distinct phase that allows exchange with, but is separated from bulk phase in which substrate, effector or inhibitor molecules are dispersed and monitored. An immobilized enzyme is physically entrapped or covalently bonded by chemicals means to an inert and usually insoluble matrix, where it acts upon it’s natural substrate.