Whether it is the use of isolated enzymes or whole cells or organisms, chemistry catalysed by enzyme systems is at the heart of industrial biotechnology. Known variously as biocatalysis, biotransformations and enzyme catalysis, Biological Catalysis, is the use of nature's catalysts (enzymes) to carry out chemical conversions.
In natural, living organisms from microorganisms up to man all of the chemistry and functional group transformation required to sustain life are effected by catalytic proteins (enzymes) which usually work in water-based systems at close to neutral pH and non-extreme temperatures. There are, of course, some extremophiles that operate in high or low temperatures, high and low acidity or in highly saline environments; these too are very useful as catalysts.
Enzyme catalysed reaction can, therefore, be carried out in benign conditions that are favourable for labile, reactive structures and do not cause degradation because of extremes of reaction parameters. The selectivity of biocatalysis can also lead to the production of chiral compounds and the ability to carry out a reaction at one specific position in a complex molecule with many similar functional groups.
The avoidance of high or low temperatures leads to energy savings and the absence of need for acidic or basic conditions avoids subsequent neutralisation and clean-up to offer advantages in effluent treatment. Together with the reduction of by-products this leads to reduced requirement for purification of products.
Applications of biological catalysis
The use of biological catalysis can be seen in reactions and processes dating back many decades and recent advances in technology have increased the rate of uptake and application across many market sectors as well as in research.
- In pharmaceuticals a wide variety of medicines are made using biological catalysis in the manufacturing route. Steroids, semi-synthetic penicillins, anti-hypertensives and anti-viral agents are just a few of the significant examples of important, and often life-saving, prescription drugs that benefit from the use of enzyme catalysed processes.
- Textile industries apply enzymes in the synthesis of indigo, an efficient method of giving a stone-washed effect to denim, preparing and bleaching cloth and making novel textiles.
- Cosmetic ingredients are increasingly being made using enzyme catalysed reactions to manufacture natural and renewable products and performance materials such as emollients, skin-lighteners, melanins and a range of anti-aging products.
- Polymers made using enzyme catalysis include polyesters and the monomeric precursor for polymers - acrylamide - is manufactured in large quantities using an enzyme reaction.
- In the food industry biological transformations are used in the production of flavour ingredients and in processing foodstuffs for juice extraction, cheese ripening and sweeteners.