Biocatalysts

Biocatalysts are biological molecules or systems that accelerate chemical reactions. The term encompasses isolated enzymes as well as whole-cell systems and, more broadly, any biological catalyst used to promote a chemical transformation. Biocatalysis generally occurs under mild conditions of temperature, pressure, and pH, often in aqueous media, and aims for high selectivity and sustainability.

Enzymes are the most common biocatalysts. They are highly specific for substrates and reactions, providing chemo-, regio-, and enantioselectivity that is difficult to achieve with conventional chemical catalysts. Whole cells, including microorganisms or engineered hosts, can perform multi-step transformations and cofactor regeneration, sometimes simplifying process design but adding biological complexity.

Advantages include reduced energy input, minimal byproducts, and the ability to operate in renewable media. Limitations include the stability of biological catalysts, sensitivity to solvents and temperature, and the cost of production and purification. Immobilization and protein engineering are used to enhance stability, reusability, and performance.

Common biocatalysts include hydrolases such as lipases and proteases, oxidoreductases such as dehydrogenases, and transferases and lyases. Industrial use spans pharmaceutical manufacturing for chiral intermediates, food and feed processing, chemical production, biodiesel, and environmental remediation through pollutant degradation.

Advances in biotechnology, including recombinant expression, directed evolution, and computational design, continue to expand the range of usable reactions and conditions. Biocatalysis is a key component of green chemistry, enabling sustainable manufacturing with reduced waste and energy requirements.