Dynamics of microbial community in the bioreactor for bisphenol S removal

Highlights: • Rapid removal of bisphenol S (50 ppm) occurred in activated sludge bioreactor. • The addition of humic acid accelerated elimination of bisphenol S. • Seven bacterial genera were likely associated with bisphenol S removal. • Humic acid increased relative abundance of Pseudomonas, Hydrogenophaga and Acidovorax. -- Abstract: Bisphenol S is one of the alternative substitutes of Bisphenol A, a chemical widely recognized as an endocrine disrupting compound. In the past few years, a variety of studies on degradation of BPA demonstrated that microorganisms play important roles in the degradation process. However, the fate of BPS during wastewater treatment processes and the composition of microorganisms that functionalize BPS degradation remain to be explored. In this study, three bioreactors, R-BPS (amended with Bisphenol S), R-BPSHA (amended with Bisphenol S and humic acid) and Con (control bioreactor), were set up to investigate the fate of BPS and the microbial compositions and dynamics in the bioreactors, especially for the microorganisms associated with BPS removal. Results showed that a complete removal was achieved within 24 days. The addition of humic acid accelerated the elimination of BPS in both effluent and sludge. The results of 16S rRNA gene ampilicon sequencing revealed that the most abundant bacteria in all samples were affiliated to Proteobacteria, Bacteroidetes, Acidobacteria and Chloroflexi. Seven major genera were likely associated with BPS removal, including Pseudomonas, Azospira, Hydrogenophaga, Devosia, Delftia, Acidovorax and Rhodobacter. Among them, humic acid increased relative abundance of some bacteria, such as Pseudomonas, Hydrogenophaga and Acidovorax. These findings would give valuable information on the microbial community composition associated with BPS removal, providing biological background for bioremediation of BPS-contaminated environment.