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 drug.
Image credit: emaze.com
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