Biocatalysis in Organic Media

Enzyme biocatalysis has evolved from reactions of molecular cleavage in aqueous medium, catalyzed mostly by hydrolases dissolved in the reaction medium, to reactions of molecular synthesis in mostly non-conventional (non-aqueous) media. The latter have a higher potential added value, so most research efforts in recent decades have been devoted to establishing technological platforms for biocatalysis in organic synthesis. Enzymes are evolved catalysts, tailored to perform under physiological conditions with exquisite chemical precision. This attribute has been exploited for making these catalysts apt to perform under the stringent conditions of organic synthesis. Several strategies of enzyme stabilization and activation have been developed and successfully applied to myriad reactions in organic synthesis of potential industrial interest. The conditions for synthesis usually require the reaction to be performed in non-aqueous systems, so enzyme biocatalysis in non-conventional media has been a subject of major attention. Interestingly, robust and readily available hydrolases can catalyze the reverse reactions of synthesis when performed in low water activity environments, opening up the opportunity for these well-known catalysts to be used in high added value processes for the synthesis of fine-chemicals, pharmaceuticals and other high-value bioactive molecules. Advances, potential and the limitations of biocatalysis in non-conventional systems for organic synthesis are reviewed with special emphasis on organic media and their compliance with green chemistry.