Antibiotics elimination by coupling ROS-mediated bond cleavage with metabolic trade-offs in electron-driven...

Synchronous mitigation of recalcitrant antibiotics and antibiotic resistance genes (ARGs) in groundwater matrices remains challenging. Here, the effects of directed electron transfer (DET) on contaminant fate and metabolic regulation were investigated in a mimetic microbial electrochemical remediation system. Results demonstrated that the degradation rate of ofloxacin and sulfachloropyridazine accelerated by 1.23-1.61 times by electrogenic respiration. The DET triggered a metabolic shift from oxidative stress response to a controlled reactive oxygen species-enzyme cascade, where catalytic hydroxyl radicals and specifically upregulated hydrolases (e.g., haloacetate dehalogenase) achieved precise cleavage of recalcitrant C-F and S-N bonds. Importantly, genomic analysis provided evidence for a metabolic competition hypothesis that the high bioenergetic cost of extracellular electron transfer ecologically selected against energy-intensive resistance mechanisms, leading to resistome attenuation. This study elucidates the metabolic trade-offs involved in controlling electron flow and enzymatic detoxification, providing a strategy for the synergistic remediation of micropollutants in simulated co-metabolic groundwater.