Biocatalysis and Biotransformation

 

Catalysts are chemicals that speed up a reaction, causes the reaction to occur but do not take part in it. Enzymes are the biological catalysts, found inside the body, catalyzing variety of reactions going on in vivo. The term “Biocatalysis” or “Biotransformation” is used when enzymes catalyze a reaction or help in transformations.

Enzymatic catalysis or biotransformation has been one fascinating area of research, flourishing over the past few decades. Enzymes obtained from animals, microorganisms, and plants have been effectively utilized for structural modification of organic compounds. The technique employs both pure enzymes and those released in whole cell cultures.

Enzymes have this intrinsic property of being specific and chiral, thus producing products with high regio- and stereoselectivities. They can be used under mild conditions and the handling is not much of a problem. These features give enzymes an edge over the chemical catalysts.

Microbial Whole Cell Cultures

 Whole cell cultures of microorganisms secrete a whole range of different types of enzymes, capable of catalyzing a variety of reactions e.g., oxidation, reduction, hydrolysis, isomerization etc. Using whole cell cultures, a single substrate may be transformed into more than one products. The problem with this technique is the low yield of the products obtained. New methodologies have been developed for attaining good yields from whole cell cultures

Pure Enzymes

Enzyme may be isolated from their sources, purified, and used for structural modification of organic compounds. The advantage of using pure enzyme is that only a single substrate with excellent yield is obtained. On the other hand, handling a pure enzyme might not be as easier as the cultures.

Protein Engineering and Recombinant Technology

For obtaining much better results, genetic engineering has been employed for producing mutant strains of microorganisms. The enzyme responsible for a particular transformation is identified, which is followed by the identification of the gene responsible for the production of that enzymes. Directed evolution is another such technique in which the proteins are engineered for obtaining desired products in good yields.

Drug Discovery

Biotransformation is an efficient technique for the production of a library of bioactive compounds, thus providing the preliminary data for the identification of lead molecules which could potentially develop into much safer and potent drugs.