Enzymes are the biocatalysts synthesized by living cells. They are complex protein molecules that bring about chemical reactions concerned with life. It is fortunate that enzymes continue to function or bring out catalysis when they are separated from the cells that are in vitro condition. Basically enzymes are nontoxic and biodegradable.
They can be produced in large amounts by microorganisms for industrial applications. Enzyme technology broadly involves production, isolation, purification and use of enzymes for the ultimate benefit of human kind. In addition recombinant DNA technology and protein engineering involved in the production of more efficient and useful enzymes are also a part of enzyme technology. The commercial production and use of enzymes is a major part of modern biotechnology industry.
Microbial enzymes have been utilised for many centuries without knowing them fully. The first enzyme produced industrially was taka diastase a fungal amylase. In 1896 in Unites States it was used as a pharmaceutical agent to cure digestive disorders.
In Europe there existed a century's old practice of softening the hides by using faeces of dogs and pigeons before tanning. A German scientist Ottorohn, demonstrated in 1905 that extracts from animal organs, pancreases from pig and cow could be used as the source of enzyme proteases for leather softening.
The utilisation of enzymes chiefly proteases for laundry purposes started in 1915. However it was not continued due to allergic reactions of impurities in enzymes. Now special techniques are available for manufacture and use of enzymes in washing powders without allergic reactions.
Commercial enzymes can be produced from a wide range of biological sources. At present a great majority of 80% of them are formed from microbial sources. The different organisms and their relative contribution for the production of commercial enzymes are given below.
A real breakthrough for large scale industrial production of enzymes from microorganisms occurred after 1950s.
Enzymes from Animal and Plant Sources
In the early days animal and plant sources largely contributed to enzymes. Even now for certain enzymes they are the major sources. Animal organs and tissues are very good sources of enzymes such as lipases, esterase and proteases. The enzyme liposome is mostly obtained from hen eggs. Some plants are excellent sources of certain enzymes like papain from papaya, bromelian from pineapple.
There are several drawbacks associated with the manufacture of enzymes from animal and plant sources. The quantities are limited and there is a wide variation in there distribution. The most important limitations are the difficulties in isolation, purification of the enzymes and the cost factor. As regards, extraction of industrial enzymes from bovine sources there is a heavy risk of contamination with bovine spongiform encephalopathy or BSE. BSE or Mad Cow Disease is a prion induced disease caused by ingestion of abnormal proteins. For these reasons microbial production of enzymes is preferred.
Enzymes from Mammalian Cell Cultures
There exists a possibility of producing commercial enzymes directly by mammalian cell cultures. But the main constraints are the cost factor which is extremely high. However certain therapeutic enzymes such as tissue plasminogen activator are produced by cell cultures.
Enzymes from Microbial Sources
Microorganisms are the most significant and convenient sources of commercial enzymes. They can be made to produce abundant quantities of enzymes under suitable growth conditions. Microorganisms can be cultivated by using inexpensive media and production can take place in a short period. In addition it is easy to manipulate microorganisms in genetic engineering techniques to increase the production of desired enzymes. Recovery, isolation and purification processes are easy with microbial enzymes than that with animal or plant sources.
In fact most enzymes of industrial application have been successfully produced by microorganisms. Various fungi, bacteria and yeasts are employed for this purpose. Some of enzymes produce by this process are amylase, cellulase, glucoseisomerase, glocoseoxidase, invertase etc...
Enzymes produced from Aspergillus Niger
Aspergillus niger is an unique organism for production of bulk enzymes. Among the microorganisms Aspergillus niger a fungus occupies a special position for the manufacture of a large number of enzymes in bulk quantities. There are well over forty commercial enzymes that are conventionally produced by Aspergillus niger. Some of these enzymes include amylase, cellulase, protease, lipase, pectinases, phytase, catalase and insulinase.
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