(493e) A Nanostructured Molecular Assembly in Ionic Liquids as a Novel Medium for Biocatalysis Reactions

The insolubility of enzymes in most ionic liquids has been overcome by the formation of molecular assembly in a hydrophobic ionic liquid stabilized by a layer of anionic surfactant sodium bis(2-ethyl-1-hexyl) sulfosuccinate (AOT) and the catalytic activity one of the enzymes studied (lipase PS) became higher than in reverse micelles of AOT in isooctane.

The technological utility of enzymes can be enhanced greatly by their use in ionic liquids rather than in conventional organic solvents or in their natural aqueous reaction media due to their unique physicochemical properties. However, one important drawback regarding the use of enzymes in ILs is the fact that they are not soluble in most ILs. In our previous study, we reported the formation of nanometer-sized water domains in a hydrophobic IL [C8mim][Tf2N] stabilized by the layer of anionic surfactant sodium bis(2-ethyl-1-hexyl) sulfosuccinate (AOT) in the presence of 1-hexanol as a cosurfactant (Chem. Phys. Chem., 2008). The present study reports that various enzymes can be solubilized in such nano-scale water domains. Our study also addresses the question of whether such dissolved enzymes show catalytic activity. It was found that the catalytic activity one of the enzymes studied (lipase PS) became higher than in microemulsions of AOT in isooctane. To the best of our knowledge, this is the first report of an enzymatic reaction being conducted in a water-in-IL microemulsion. This work may open up new possibilities for studying enzymes in ionic liquids, which are receiving increasing attention as ?green' solvents for organic synthesis and catalytic processes.