Controlled Immobilization of a Palladium Complex/Laccase Hybrid into a Macrocellular Siliceous Host
Abstract
This study investigates the site-directed immobilization of a hybrid catalyst bearing a biquinoline-based-Pd(II) complex (1) and a robust laccase within cavities of a silica foam to favor veratryl alcohol oxidation. We performed the grafting of 1 at a unique surface located lysine of two laccase variants, either at closed (1⊂UNIK 157) or opposite position (1⊂UNIK 71) of the enzyme oxidation site. After immobilization into the cavities of silica monoliths bearing hierarchical porosity, we show that catalytic activity is dependent on the orientation and loading of each hybrid, 1⊂UNIK 157 being twice as active than 1⊂UNIK 71 (203 TON vs 100 TON) when operating under continuous flow. These systems can be reused 5 times, with an operational activity remaining as high as 40 %. We show that the synergy between 1 and laccase can be tuned within the foam. This work is a proof of concept for controlling the organization of a heterogeneous hybrid catalyst using a Pd/laccase/silica foam.
Origin : Publication funded by an institution