Mesoporous titania thin films as efficient enzyme carriers for paraoxon determination/detoxification: effects of enzyme binding and pore hierarchy in biocatalyst activity and reusability

Abstract

The aims of this work were to efficiently immobilize organophosphate degrading enzyme, His6-OPH, on hierarchical mesoporoustitania thin films and further, to use this biocatalyst films as efficient tools in the detection/detoxofication of pesticides, paraoxon in our case. His6-OPH was immobilized on mesoporous thin films with uniform (9nm) and bimodal (13-38nm) pore size distribution, through covalent attachment and physical adsorption. The biocatalyst films show good activity, and enhanced stability with respect to the free enzyme at extreme conditions of pH and temperature, especially around neutral pH and room temperature. In addition, they can be easily separated from the reaction media and reused multiple times without significant loss in activity.