New Ionic Liquids with Buffering and Chelating Abilities for Enzyme Engineering

Ionic liquids (ILs) with buffering and chelating abilities were designed and synthesized on the basis of ethylenediaminetetraacetic acid (EDTA) for the development of buffered enzymatic IL systems and for enzymatic reaction in heavy metal containing aqueous system. Transesterification activity of Candida antarctica lipase B dissolved in the hydroxyl-functionalized IL was buffer dependent. High activity and outstanding stability was obtained with the buffered enzymatic IL systems for the transesterification. In heavy metal containing aqueous system, EDTA IL buffers as Hg2+ chelators protected horseradish peroxidase (HRP) against Hg2+-induced denaturation and precipitation. Higher pH favored the protection, while at lower pH the protection diminished. We can conclude that the new ILs possess both buffering and chelating abilities.