The anaerobic ammonium oxidation (anammox) process is regarded as a promising approach to treat antibiotic-containing wastewater. Therefore, it is urgent to elucidate the effects of various antibiotics on the anammox process. Moreover, the mechanism of extracellular polymeric substance (EPS) as protective barriers to relieve antibiotic stress remain unclear. Therefore, the single and combined effects of erythromycin (ETC) and sulfamethoxazole (SMZ), and interactions between EPS and antibiotics were investigated in this study. Based on a 228-day continuous flow experiment, high concentrations of ETC and SMZ had significant inhibitory effects on the nitrogen removal performance of the anammox process, with the abundances of corresponding antibiotic resistance genes (ARGs) increasing. In addition, the combined inhibitory effect of the two antibiotics on the anammox process was more significant and longer-lasting than that of the single. However, the anammox process was able to quickly recover from deterioration. The tolerance of anammox granules to the stress of low-concentration antibiotics was probably attributed to the increase in ARGs and secretion of EPS. Molecular docking simulation results showed that proteins in EPS could directly bind with SMZ and ETC at the sites of GLU-307, HYS-191, ASP-318 and THR-32, respectively. These findings improved our understanding of various antibiotic effects on the anammox process and the interaction mechanism between antibiotics and proteins in EPS.

厌氧氨氧化（anammox）工艺被认为是处理含抗生素废水的一种有前途的方法。因此，阐明各种抗生素对厌氧氨氧化过程的影响迫在眉睫。此外，细胞外聚合物（EPS）作为缓解抗生素应激的保护屏障的机制仍不清楚。因此，本研究调查了红霉素 (ETC) 和磺胺甲恶唑 (SMZ) 的单一和联合作用，以及 EPS 和抗生素之间的相互作用。基于228天的连续流动实验，高浓度的ETC和SMZ对厌氧氨氧化工艺的脱氮性能有显着的抑制作用，相应的抗生素抗性基因（ARGs）的丰度增加。此外，两种抗生素联合使用对厌氧氨氧化过程的抑制作用比单一抗生素更显着且持续时间更长。然而，厌氧氨氧化工艺能够迅速从恶化中恢复。厌氧氨氧化颗粒对低浓度抗生素胁迫的耐受性可能归因于ARGs的增加和EPS的分泌。分子对接模拟结果表明，EPS 中的蛋白质可以分别与 GLU-307、HYS-191、ASP-318 和 THR-32 位点的 SMZ 和 ETC 直接结合。这些发现提高了我们对各种抗生素对厌氧氨氧化过程的影响以及抗生素与 EPS 中蛋白质相互作用机制的理解。厌氧氨氧化工艺能够迅速从恶化中恢复。厌氧氨氧化颗粒对低浓度抗生素胁迫的耐受性可能归因于ARGs的增加和EPS的分泌。分子对接模拟结果表明，EPS 中的蛋白质可以分别与 GLU-307、HYS-191、ASP-318 和 THR-32 位点的 SMZ 和 ETC 直接结合。这些发现提高了我们对各种抗生素对厌氧氨氧化过程的影响以及抗生素与 EPS 中蛋白质相互作用机制的理解。厌氧氨氧化工艺能够迅速从恶化中恢复。厌氧氨氧化颗粒对低浓度抗生素胁迫的耐受性可能归因于ARGs的增加和EPS的分泌。分子对接模拟结果表明，EPS 中的蛋白质可以分别与 GLU-307、HYS-191、ASP-318 和 THR-32 位点的 SMZ 和 ETC 直接结合。这些发现提高了我们对各种抗生素对厌氧氨氧化过程的影响以及抗生素与 EPS 中蛋白质相互作用机制的理解。分别是 ASP-318 和 THR-32。这些发现提高了我们对各种抗生素对厌氧氨氧化过程的影响以及抗生素与 EPS 中蛋白质相互作用机制的理解。分别是 ASP-318 和 THR-32。这些发现提高了我们对各种抗生素对厌氧氨氧化过程的影响以及抗生素与 EPS 中蛋白质相互作用机制的理解。