Enzyme-triggered approach to reduce water bodies' contamination using peroxidase-immobilized ZnO/SnO₂/alginate...

Enzyme immobilization on solid support offers advantages over free enzymes by overcoming characteristic limitations. To synthesize new stable and hyperactive nano-biocatalysts (co-precipitation method), ginger peroxidase (GP) was surface immobilized (adsorption) on ZnO/SnO₂ and ZnO/SnO₂/SA nanocomposite with immobilization efficacy of 94 % and 99 %, respectively. Thereafter, catalytic and biochemical characteristics of free and immobilized GP were investigated by deploying various techniques, i.e., FTIR, PXRD, SEM, and PL. Diffraction peaks emerged at 2θ values of 26°, 33°, 37°, 51°, 31°, 34°, 36°, 56°, indicating the formation of SnO₂ and ZnO. The OH stretching of the H₂O molecules was attributed to broad peaks between 3200 and 3500 cm^-1, whereas ZnO/SnO₂ spikes occurred in the 1626-1637 cm^-1 range. SnO stretching mode and ZnO terminal vibrational patterns have been verified at corresponding wavelengths of 625 cm^-1 and 560 cm^-1. Enzyme entrapment onto substrate was verified via interactions between GP and ZnO/SnO₂/SA as corroborated by signals beneath 1100 cm^-1. GP-immobilized fractions were optimally active at pH 5, 50 °C, and retained maximum activity after storage of 4 weeks at -4 °C. Kinetic parameters were determined by using a Lineweaver-Burk plot and V_max for free GP, ZnO/SnO₂/GP and ZnO/SnO₂/SA/GP with guaiacol as a substrate, were found to be 322.58, 49.01 and 11.45 (μM/min) respectively. A decrease in values of V_max and K_M indicates strong adsorption of peroxidase on support and maximum affinity between nano support and enzyme, respectively. For environmental remediation, free ginger peroxidase (GP), ZnO/SnO₂/GP and ZnO/SnO₂/SA/GP fractions effectively eradicated highly intricate dye. Multiple scavengers had a significant impact on the depletion of the dye. In conclusion, ZnO/SnO₂ and ZnO/SnO₂/SA nanostructures comprise an ecologically acceptable and intriguing carrier for enzyme immobilization.