Electrode-assisted biodegradation of methylparaben (MEP): A sustainable approach for efficient degradation and toxicity management

The widespread occurrence of methylparaben (MEP) in aquatic systems raises concerns due to its persistence and associated ecological risks. This study investigates the application of an electrode-assisted biodegradation system (EBS) as a coupled strategy to enhance both degradation efficiency and toxicity reduction. Compared with open circuit and abiotic controls, the EBS achieved markedly higher MEP removal (98.48% within 7 days), accompanied by substantial mineralization (77.09% total organic carbon removal). The improved performance was associated with enhanced microbial activity, reflected by elevated protein content and increased activities of key enzymes involved in ester hydrolysis and aromatic ring transformation. Intermediates identified through high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) analysis supported a plausible degradation pathway leading to complete mineralization. Beyond removal efficiency, the biological impact of treated effluents was assessed using Artemia salina. Untreated samples caused noticeable developmental inhibition, mortality, and oxidative stress, whereas EBS-treated effluents maintained physiological and biochemical responses comparable to the control. The normalization of antioxidant biomarkers, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), together with the damage-related biomarker lactate dehydrogenase (LDH), further confirmed effective detoxification. Collectively, the results demonstrate that electrochemically assisted biodegradation not only accelerates MEP removal but also mitigates its associated toxicity, highlighting its potential for sustainable wastewater treatment applications.