engleski

The novel Technologies for the Use of Biocatalysts and Biotransformations

Throughout the history of mankind, microorganisms have been of tremendous social and economic importance. In the course of time, it was discovered that microorganisms could modify certain compounds by simple, chemically well-defined reactions, which were further catalyzed by enzymes. Nowadays, these processes are called "biotransformations" Biotransformations are reactions in "one or two-steps" where the chemical structures of the substrate and product resemble one another. The reactions are catalyzed by isolated enzymes or enzymes in whole cells. These enzyme forms are named biocatalysts (Vasić-Rački, 2000) In comparison to fermentation processes fewer side-products are formed in enzymatic biotransformations, complex expensive fermentors are not required, aeration, agitation and sterility need not necessarily be maintained and substrate is not diverted into the formation of de novo cellular biomass. Isolated biocatalysts are especially useful if the reaction they catalyze is about to be completed, if they are resistant to product inhibition, and if they are active in the presence of low concentration of substrate (such as in detoxification reaction where pollutants are present in the waste stream). “ One-pot” multi-enzyme reactions are much more feasible than a combined use of several chemical catalysts or reagents, especially as the latter often have be used in reactors made of special resistant materials to tolerate extreme conditions, such as the use of concentrated acids under elevated temperatures and pressures.

biocatalysts; biotransformations; malic acid; pyruvic acid; L-tert leucine

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