Strategies for Improving the Catalytic Performance of an Enzyme in Ionic Liquids

As media for an enzymatic reaction, ionic liquids (ILs) have many advantages over conventional molecular organic solvents, but some drawbacks still remain unsolved. In this review, we focus our attention on the various strategies that have been tried in recent years for improving the enzymatic performance in ILs. For clarity, this review is divided into several parts based on the hydrophilicity/hydrophobicity of ILs. For hydrophobic ILs, we put the emphasis on the construction of new macroscopically homogenous but microscopically heterogenous water-in-IL microemulsion systems and the catalytic performance of solubilized enzymes in them. For hydrophilic ILs, we highlight the enzyme performance related Hofmeister anions or cations series and the surface active effect of ILs.