Stabilization of Candida rugosa lipase on nanosized zirconia-based materials

We synthesized and characterized three novel materials on the basis of zirconia. Despite their three-to six fold higher specific surface area, nanoZrO(2)-CeO2 (150 m(2)/g) and nanoZrO(2)-B (296 m(2)/g) they proved to be less effective supports for a lipase from Candida rugosa than nanoZrO(2)-A. For the last, we achieved protein loading of 23 mg/g, distributed in a monolayer, which means that 61% of the carrier surface was occupied by the protein. The immobilized on nanoZrO(2)-A lipase (nanoZrO(2)-A-CRL) exhibited enhanced thermal and solvent stability in comparison to the native enzyme. NanoZrO(2)-A-CRL has a half-life at 55 degrees C of 73 min, while for the native enzyme it was only 5.3 mm. The immobilized enzyme preserved 20% of its activity in six consecutive cycles of the reaction hydrolysis of tributyrin. The immobilization influenced the enantioselectivity of CRL Using nanoZrO(2)-A-CRL under optimal reaction condition in the reaction of esterification of lauric acid with (+/-)-menthol, we achieved menthol conversion of 43% (i.e. 82% of (-) methyl laurate), enantiomeric excess of 97% and enantiomeric ratio of 144. The conformational analysis proved that upon immobilization no serious change in the secondary structure of the lipase from Candida rugosa had occurred. (C) 2014 Elsevier B.V. All rights reserved.