Biotransformations

Abstract

Biotransformations using enzymes and whole microbial cells have been used for centuries to produce foods and beverages. However, only in the last century have we developed methods to understand and improve biocatalyst stability and productivities. Engineering and directed evolution of enzymes have enhanced enzymatic activity and increased the number of products obtainable by biotransformation. The understanding of the mechanisms of cellular adaptation to environmental conditions also allowed the use of microbial cells in non-aqueous biocatalytic systems. Both free and immobilized enzymes and microorganisms have been used successfully in different media, including aqueous, aqueous:organic and organic solvents, gas:solid systems, supercritical fluids and ionic liquids. Extremophiles also contributed significantly to the development of biotransformation processes as they are a source of enzymes able to work in environments of extreme temperature, pH and ionic strength.