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Abstract
Adsorption and catalytic activity of lipases A and B from Candida Antarctica (Novozym 735 and Novozym CALB Liquid) on planar silica and gold surfaces, as well as on gold surfaces grafted with either saturated or fluorinated alkanethiols, have been studied by means of the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. Amounts adsorbed, binding affinity, layer thickness, and rigidity of adsorbed layers have been determined and comparatively assessed in terms of reaction rates in a transesterification reaction between 1-hexanol and vinylbutanoate. The fluorinated surface provided the highest amount of immobilized CAL-A, and a systematic increase in the activity of CAL-A as the hydrophobicity of the support increased was also observed. CAL-B displayed increasing surface coverage with increasing hydrophilicity, while normalized values for initial conversion rates of CAL-B showed low activity when adsorbed onto a fluorinated surface, as compared to the other surfaces.
We gratefully acknowledge the Research Council of Norway (NFR) for financial support within the NANOMAT program, project no. 163529/S10 and project no. 177556, under the FRINAT program. We also thank Novozymes (Denmark) for the kind gifts of Novozym CALB L and Novozym 735.
Notes
Part of the special issue, Surface and Colloid Chemistry Without Borders: An International Festschrift for Professor Per Stenius on the Occasion of His 70th Birthday.