Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu College of Water Treatment Technology and Material Collaborative Innovation Center, Suzhou 215009, China.
Sci Total Environ. 2020 Nov 10;742:140481. doi: 10.1016/j.scitotenv.2020.140481. Epub 2020 Jun 24.
Suspended activated sludge (AS) and carrier-attached biofilms simultaneously exist in an integrated fixed film activated sludge (IFAS) system. However, the differentiation of antibiotic resistance genes (ARGs) and microbial communities in different types of biofilms is rarely reported. In this study, successions of ARGs and microbial communities of AS and two types of suspended carrier-attached biofilms over seasons were investigated in the IFAS system of one municipal wastewater treatment plant. Results showed that substantial differences were found in the distribution pattern of ARGs, bacterial communities, and predicted microbial function between AS and attached biofilms. The relative abundances of all detected ARGs in AS were significantly higher than those in attached biofilms. ARGs with higher relative abundances generally existed in K3 carrier (surface area ≥ 800 m/m) attached biofilms than those in K1 carrier (surface area ≥ 450 m/m) biofilms. The relative abundances of ARGs were negatively correlated with temperature and biochemical oxygen demand (BOD) and positively correlated with ammonium nitrogen contents for AS but not for attached biofilms. No significant relationship was found between the extracellular polymeric substance (EPS) content and ARG abundance for all samples. Temperature, BOD, and ammonium nitrogen contents were closely connected to microbial communities. The Bray-Curtis distance of bacterial communities between two adjacent sampling seasons for AS was larger than those of two attached biofilms. Network analysis indicated that the AS network had more positive links and intense connections than the attached biofilm networks, potentially facilitating the dissemination of ARGs. The differential distribution of ARGs among the three types of samples was significantly correlated with the microbial co-occurrence network topological properties. Bray-Curtis distance and network analysis suggest that microbial community is more robust in attached biofilms than in suspended AS. This work provides a more in-depth understanding of ARGs and microbial community distributions in wastewater biofilms.
悬浮活性污泥 (AS) 和载体附着生物膜同时存在于一体化固定膜活性污泥 (IFAS) 系统中。然而，不同类型生物膜中抗生素抗性基因 (ARGs) 和微生物群落的分化很少有报道。本研究在一个城市污水处理厂的 IFAS 系统中，调查了不同季节 AS 和两种悬浮载体附着生物膜中 ARGs 和微生物群落的演替。结果表明，ARGs、细菌群落和预测微生物功能在 AS 和附着生物膜之间的分布模式存在显著差异。AS 中所有检测到的 ARGs 的相对丰度明显高于附着生物膜。相对丰度较高的 ARGs 一般存在于 K3 载体（表面积≥800 m/m）附着生物膜中，而不是 K1 载体（表面积≥450 m/m）生物膜中。ARGs 的相对丰度与温度、生化需氧量 (BOD) 呈负相关，与氨氮含量呈正相关，但与附着生物膜无关。对于所有样品，EPS 含量与 ARG 丰度之间没有发现显著关系。温度、BOD 和氨氮含量与微生物群落密切相关。AS 相邻两个采样季节之间细菌群落的 Bray-Curtis 距离大于两个附着生物膜。网络分析表明，AS 网络的正连接和连接强度比附着生物膜网络更大，可能促进了 ARGs 的传播。三种类型样品之间 ARGs 的差异分布与微生物共现网络拓扑特性显著相关。Bray-Curtis 距离和网络分析表明，附着生物膜中的微生物群落比悬浮 AS 更具弹性。这项工作提供了对废水生物膜中 ARGs 和微生物群落分布的更深入理解。
