Effect of triclosan on partial denitrification, microbial community and antibiotic resistance genes (ARGs) of a sequencing biofilm batch reactor (SBBR)

The effects of triclosan (TCS) on the performance, extracellular polymeric substances (EPS), microbial community and antibiotic resistance genes (ARGs) of a sequencing batch bio?lm reactor (SBBR) were evaluated during partial denitrification. The protein (PN) contents were always higher than polysaccharide (PS) contents in both loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS), and the content of TB-EPS was higher than LB-EPS. The community structure of biofilm was obviously different from that of floccular sludge, and it was similar in biofilm and floccular sludge at 5 mg/L TCS. Pseudomonas, Aeromonas, Shewanella and Thaurea were predominant genera. The abundance of nirS was relatively stable and was higher than narG and nosZ.mexF, acrA-02, fabK, etc was screened only when TCS concentration was 5 mg/L.