Simultaneous high-efficiency removal of sulfamethoxazole and zinc (II) from livestock and poultry breeding wastewater by a novel dual-functional bacterium, Bacillus sp. SDB4

The complex mixtures of antibiotics and heavy metals are commonly existed in livestock and poultry breeding wastewater. Effective and simultaneous removal of these toxic compounds by microorganisms, especially single strains, remains a considerable challenge. In this study, a novel functional strain SDB4, isolated from duck manure and identified as Bacillus sp., has been shown to possess high removal capabilities for both sulfamethoxazole (SMX) and Zn 2+ . The maximum removal efficiency achieved 73.97% for SMX and 84.06% for Zn 2+ within 48 h in the single pollution system. It has great potential for eliminating SMX along with Zn 2+ , 78.45% of SMX and 52.91% of Zn 2+ were removed in the 20 mg·L -1 SMX and 100 mg·L -1 Zn 2+ binary system. Furthermore, the SMX-biotransformation capability of SDB4 was enhanced at low concentrations of Zn 2+ (below 100 mg·L -1 ). The SMX biotransformation and Zn 2+ adsorption data fitted well with the pseudo-first-order kinetic model, indicating that the two pollutants were in accordance with the same removal rule. N 4 -acetyl-SMX was identified as the main stable transformation product during SMX removal. FTIR analyses revealed that OH, NH 2 , C=O, C-N/N-H, and C-O-C played major roles in the adsorption of Zn 2+ . Our study of the dually functioning strain SDB4 provides a potential application for the simultaneous biological removal of antibiotics and heavy metals.