Weak electrostimulation enhances biodegradation of meta-cresol: Unravelling functional mechanisms, microbial interaction and biotoxicity assessment

Phenolic pollutants in wastewater pose significant threats to both ecosystems and human health. In this study, a weak electrostimulation-mediated anaerobic degradation (ED) system was constructed to treat wastewater containing meta-cresol (m-cresol). The ED system achieved efficient m-cresol removal within 72 h, with a total organic carbon (TOC) removal efficiency of 89.32 ± 3.38%. In contrast, a control system (without electrostimulation) required 120 h for comparable removal. The underlying enhancement mechanism was elucidated through analyses of degradation pathways, toxicity reduction, functional enzyme activities, and microbial community interactions. Results showed that weak electrostimulation significantly enriched electroactive bacteria (39.01%) and potential degrading bacteria (20.22%), alongside the upregulation of functional genes involved in phenolic compound metabolism. The functional microbial consortium synergistically drove m-cresol biodegradation through demethylation, dehydroxylation, esterification, and ring-opening oxidation pathways, ultimately leading to mineralization and superior detoxification performance. This study demonstrates that the weak electrostimulation-mediated anaerobic biodegradation system can overcome limitations of traditional biological treatment, providing new insights for designing efficient and low-risk strategies to treat highly toxic phenolic wastewater.