Ionic liquid facilitates biocatalytic conversion of hardly water soluble ketones

Ionic liquids represent a promising alternative to conventional cosolvents as biocompatible solubilisers for biocatalysis. This was shown using water miscible ionic liquids to facilitate the stereoselective reduction of hardly water soluble, aliphatic ketones catalysed by the alcohol dehydrogenase from Lactobacillus brevis. Ten ionic liquids were screened for activity and solubility. Improved storage stabilities besides improved enzyme activities, as well as reduced substrate surplus and product inhibitions were found, while applying the most promising AMMOENG™ 101 in more detailed investigations. Batch reactions with cofactor regeneration via a glucose dehydrogenase showed increased reaction rates; thus underlining the positive influence of AMMOENG™ 101. For (R)-3-octanol, (R)-2-nonanol, (R)-2-decanol, and (R)-2-octanol space time yields between 250 and 350 mmol L−1 d−1 were achieved.