Biocatalysis in semi-aqueous and nearly anhydrous conditions.

In the past few years there have been prolific advances in activating enzymes for nonaqueous biocatalysis. Molecular dynamics simulations complement recent experimental results and offer new insights into the deleterious effects of organic solvents, such as water stripping and active-site penetration. Methods for activating enzymes in semi-aqueous or nonaqueous media include protein engineering, chemical modification, and co-lyophilization with non-buffer salts. Enzyme immobilization on novel polymeric supports and the use of zeolite molecular sieves can also increase solvent tolerance, enhance activity, and improve enantioselectivity. The recent implementation of enzymes in ionic liquids has also led to better long-term stability relative to traditional organic solvents and the simultaneous solubilization of enzymes, cofactors and substrates.