Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
J Hazard Mater. 2022 Mar 5;425:127764. doi: 10.1016/j.jhazmat.2021.127764. Epub 2021 Nov 12.
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.
抗生素可以通过共代谢和代谢作用在活性污泥中生物降解。在这项研究中，我们通过好氧污泥、混合污泥和硝化污泥，研究了不同自养和异养微生物中磺胺甲恶唑（SMX）的生物降解途径和抗生素抗性基因（ARGs）的命运。在不同的活性污泥系统中发现并证明了磺胺甲恶唑激活抗生素降解初期降解途径的阈值浓度。异养细菌在 SMX 生物降解中发挥了重要作用。然而，氨氧化细菌（AOB）具有更快的代谢率，约是异养细菌的 15 倍，通过共代谢对 SMX 的去除贡献很大。随着 SMX 浓度的增加，由于功能异养细菌的富集，好氧污泥中的 amoA 基因和 AOB 相对丰度降低，而在硝化污泥中增加。微生物群落分析表明，具有 SMX 去除和抗生素抗性能力的功能细菌被 SMX 压力选择。潜在的 ARGs 宿主可以增加其对 SMX 的生物毒性的抗性并维持系统性能。这些发现对指导废水处理厂中的抗生素生物降解和 ARGs 控制具有实际意义。
