The key active degrader, metabolic pathway and microbial ecology of triclosan biodegradation in an anoxic/oxic system

A lab-scale anoxic/oxic (A/O) system was used to reveal the key active triclosan-degrading bacteria (TCS-DB) in this study. The results showed that TCS was mainly removed by metabolism of heterotrophic bacteria (accounting for about 62%), and the potential metabolic pathway was the break of ether bond in TCS formed 2,4-dichlorophenol, and further dechlorination formed phenol or other metabolic end products. DNA-based stable isotope probing (DNA-SIP) assay further revealed that Methylobacillus accounting for 20.75% in C-13 sample was the key active TCS-DB. Furthermore, methylotrophy and methanol oxidation were found to be the potential metabolic routes of TCS degradation by functional annotation of prokaryotic taxa analysis. Interestingly, TCS accelerated the propagation of antibiotic resistance genes (fabI) and inti1 which positively correlated with several functional microorganisms (p < 0.05). This study contributes to comprehend the potential mechanism, metabolic pathway and microbial ecology of TCS biodegradation in A/O system.