Sustainable biodegradation of phenol using peroxidases extracted from local agricultural wastes

The present study focused on the enhanced biodegradation of phenol as a toxic compound using peroxidases extracted from agricultural wastes (skin peels of luffa and jicama plants) mediated bioprocess under H₂O₂-infusion. The extracted crude luffa peroxidase (LP) and jicama peroxidase (JP) showed enzyme activities of 1.4 ± 0.2 U/mL and 1.6 ± 0.1 U/mL, respectively. LP achieved a phenol removal efficiency exceeding 95% at H₂O₂ concentrations between 6-8 mM and pH 7, whereas JP achieved 94.5% removal at pH 7, with minimal impact from variations in H₂O₂ concentrations. Maximum removal efficiencies for both peroxidases were observed at an enzyme loading of 1.5 mL. LP demonstrated effective removal within a temperature range of 25 °C to 30 °C, while JP maintained functionality up to 40 °C. The optimum reaction times were determined to be 16 h for LP and 13 h for JP. LP exhibited high preservation of enzyme activity during storage, with no significant fluctuations observed, while JP's enzyme activity decreased to approximately 40% of its initial value, accompanied by a notable decline in phenol elimination efficiency by day 42. First-order kinetic analysis of enzyme activity yielded reaction rate constants of 1.18 h^-1 for LP and 1.21 h^-1 for JP, with JP demonstrating superior storage stability compared to LP.