Microbial synergistic metabolic mechanism of enhanced tetrabromobisphenol A removal by bio-electrochemical system coupled constructed wetland

Abstract

The widespread existence of tetrabromobisphenol A (TBBPA) in the aquatic environment requires efficient treatment technology. The feasibility and related molecular mechanisms for the simultaneous deep removal of nitrate and TBBPA in a bio-electrochemical system coupled with a constructed wetland (BES-CW) are unclear. This study fabricated the BES-CW to achieve simultaneously deep removal of nitrate and TBBPA. TBBPA majorly went through reductive debromination, hydrolytic debromination, ring-cleavage, and oxidation in the open and closed circuits of BES-CW. Electricity activated key genes encoded in oxidoreductase (pflA, pflX) and oxygenase (dmpB, pobA) from electroactive bacteria (Geobacter and Desulfovibrio), accelerating TBBPA metabolites' oxidation and mineralization. Nitrate enriched the Acinetobacter and stimulated genes encoded in hydrolytic dehalogenase, inducing TBBPA hydrolytic debromination and further mineralization. Electricity and nitrate synergistically enhance TBBPA degradation and mineralization, guiding the advanced treatment of emerging pollutants in the aquatic environment.

Keywords: Degradation pathway; Denitrification; Key genes; Microbial community; TBBPA degradation.