摘要
      抗生素可以在活性污泥中通过共代谢和代谢进行生物降解。在本研究中，我们采用好氧污泥、混合污泥和硝化污泥，研究了磺胺甲恶唑（SMX）和抗生素抗性基因（ARGs）在不同自养和异养微生物中的生物降解途径。在不同的活性污泥系统中，发现并证明了SMX在抗生素降解初始阶段激活降解途径的阈值浓度。异养细菌在SMX的生物降解中起着重要作用。然而，氨氧化细菌（AOB）的代谢速率更快，约为异养细菌的15倍，通过共代谢对SMX的去除有很大贡献。随着SMX浓度的增加，由于功能性异养细菌的富集，好氧污泥中的amoA基因和AOB相对丰度降低，而硝化污泥中的相对丰度增加。微生物群落分析表明，通过SMX压力筛选出具有SMX去除能力和抗生素耐药性的功能菌。潜在的ARGs宿主可以增加其对SMX生物毒性的抵抗力，并保持系统性能。这些发现对指导废水处理厂的抗生素生物降解和ARGs控制具有实际意义。
Abstract
Antibiotics can be biodegraded in activated sludge via co-metabolism and metabolism. In this study, we investigated the biodegradation pathways of sulfamethoxazole (SMX) and antibiotic resistant genes’ (ARGs) fate in different autotrophic and heterotrophic microorganisms, by employing aerobic sludge, mixed sludge, and nitrifying sludge. A threshold concentration of SMX activating the degradation pathways in the initial stage of antibiotics degradation was found and proved in different activated sludge systems. Heterotrophic bacteria played an important role in SMX biodegradation. However, ammonia-oxidizing bacteria (AOB) had a faster metabolic rate, which was about 15 times higher than heterotrophic bacteria, contributing much to SMX removal via co-metabolism. As SMX concentration increases, the amoA gene and AOB relative abundance decreased in aerobic sludge due to the enrichment of functional heterotrophic bacteria, while it increased in nitrifying sludge. Microbial community analysis showed that functional bacteria which possess the capacity of SMX removal and antibiotic resistance were selected by SMX pressure. Potential ARGs hosts could increase their resistance to the biotoxicity of SMX and maintain system performance. These findings are of practical significance to guide antibiotic biodegradation and ARGs control in wastewater treatment plants.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421027333