biocatalizare

Biocatalizare, or biocatalysis, is the use of natural catalysts—enzymes or whole cells—to accelerate chemical reactions. It encompasses enzymatic reactions in purified form and bioprocesses within living organisms. Biocatalysis is widely used in pharmaceuticals, fine chemicals, food, and environmental applications.

Enzymes work by binding substrates in active sites, lowering activation energy and providing high regio-, chemo-, and enantioselectivity. They typically operate under mild conditions in aqueous media, at moderate temperatures and near-neutral pH, producing fewer byproducts and enabling cleaner processes. Many reactions require cofactors or cofactor recycling systems.

Approaches include free enzymes in solution, immobilized enzymes on solids for reuse, and whole-cell catalysis in which cellular metabolism drives the transformation. Reactions can also occur in non-aqueous or biphasic media, with cofactors regenerated enzymatically or chemically.

Common enzymes and reactions: lipases catalyze esterifications; proteases modify peptides; transaminases form amines; dehydrogenases and oxidases perform redox steps; lactases hydrolyze lactose; many enzymes enable stereoselective synthesis of chiral building blocks.

Applications: production of chiral pharmaceutical intermediates, agrochemicals, flavors and fragrances, food processing, biofuels, and environmental cleanup. Biocatalysis can reduce waste, energy use, and metal catalysts, contributing to greener manufacturing.

Challenges include limited substrate scope and stability, enzyme cost and production, and the need for efficient cofactor recycling and scale-up. Immobilization and protein engineering help address these issues.

History and outlook: knowledge emerged from enzymology in the 19th-20th centuries, with significant advances from recombinant DNA technology and directed evolution. Future directions include computational enzyme design, non-aqueous biocatalysis, flow bioprocesses, and integrated biocatalytic cascades.