Influence of CeO₂ nanoparticles synthesized from plant extracts on the catalytic performance of isolated catalase from carrots

This paper describes the green synthesis of well-crystalline CeO₂ nanoparticles (NPs) using the extract of lemon leaves (Citrus limon) and efficiently used as substituted catalase to catalyze the various catalase enzyme. The spherical particles along with typical face-center cubic crystalline phase were observed for CeO₂ NPs which were further characterized in terms of compositional, structural, surface, and enzyme catalytic properties. Catalase was isolated from carrots (Daucus carota). The optimum pH and temperature for catalase activity was found to be 6.0 and 35 °C, respectively. K_m value was found to be 17 mM calculated from the double reciprocal plot. The enzyme was found to be an eco-friendly reagent for oxidation of toxic compounds like phenols, acetaldehydes, acetic acid, and sodium nitrite. CeO₂ nanoparticles biomimic catalase and degrade H₂O₂ efficiently. Optimum pH and temperature for catalase-like activity by CeO₂ nanoparticles were found to be 6.0 and 30 °C, respectively. K_m value was found to be 14.96 mM from the double reciprocal plot. Comparative studies of catalase and CeO₂ nanoparticles with respect to kinetic parameters like pH, temperature, and Michaelis–Menten constant K_m have been established.