Dissolution of Candida antarctica lipase B in ionic liquids: effects on structure and activity

The effects of ionic liquid media on the activity of Candida antarctica lipase B in a simple transesterification reaction were studied. In ionic liquids containing alkylsulfate, nitrate and lactate anions, which dissolved CaLB, the reaction was at least ten times slower than in [BMIm][BF4]. Only [Et3MeN][MeSO4] was an exception, as dissolved CaLB maintained its activity in this solvent. By means of FT-IR spectroscopy, denaturation of CaLB was observed upon dissolution in ionic liquids in which the activity was low, whereas the conformation of enzyme dissolved in [Et3MeN][MeSO4] closely resembled the native one.