Mechanistic insights into efficient phenol degradation mediated by anodic respiration in Acinetobacter sp. LA-1

Phenol is a persistent aromatic pollutant frequently detected in industrial wastewater. In this study, an Acinetobacter sp. LA-1 capable of simultaneous phenol degradation and anodic electricity generation was enriched and evaluated in microbial fuel cells (MFCs). Closed-circuit operation significantly improved phenol removal efficiency and power output compared to the open-circuit control. Integrated multi-omics analyses combining genomic, metabolomic, and electrochemical characterizations demonstrated that anodic respiration efficiently enhances phenol degradation and extracellular electron transfer (EET), and the enhanced phenol degradation rate supplies a greater amount of acetyl-CoA for the tricarboxylic acid cycle (TCA cycle), thereby supporting increased microbial respiration. Genes associated with catechol ortho-cleavage, TCA cycle and electron transport chain activity were upregulated. The redirected electron flux from intracellular respiration toward the anode strengthened proton motive force formation, resulting in elevated Adenosine Triphosphate (ATP) synthesis and enhanced Coulombic efficiency. These findings provide mechanistic insight into the coupling between phenol oxidation and anodic respiration in Acinetobacter sp. LA-1 and highlight its potential for sustainable treatment of phenol-containing wastewater with concurrent bioenergy recovery.