School of Energy and Environment, Southeast University, Nanjing, 210096, China.
School of Civil Engineering, Southeast University, Nanjing, 210096, China.
Environ Pollut. 2020 Oct;265(Pt B):115084. doi: 10.1016/j.envpol.2020.115084. Epub 2020 Jun 23.
The effects of the continuous accumulation of Zinc (Zn) on the fate of antibiotic resistance genes (ARGs) in constructed wetland-microbial fuel cells (CW-MFCs) remain unclear. In this study, the impacts of Zn addition and a circuit mode on antibiotic removal, occurrence of ARGs, the bacterial community, and bacterial functions were investigated in three groups of CW-MFCs. The results showed that continuous Zn exposure enriched the target ARGs during the initial stage, while excessive Zn accumulation decreased antibiotic removal and the abundance of ARGs. A principal component analysis demonstrated that ARGs and the bacterial community distribution characteristics were significantly impacted by the mass accumulation of antibiotics and Zn, as well as the circuit mode. A redundancy analysis, partial least squares path modeling, and Procrustes analysis revealed that the accumulation of antibiotics and Zn, the composition of the bacterial community, the circuit mode, and the abundance of intI associated with horizontal gene transfer jointly contributed to the distributions of ARGs in the electrodes and effluent. Moreover, continuous exposure to Zn decreased the bacterial diversity and changed the composition and function of the bacterial community predicted using PICRUSt tool. The co-occurrence of ARGs, their potential hosts and bacterial functions were further revealed using a network analysis. A variation partition analysis also showed that the accumulation of target pollutants and the circuit mode had a significant impact on the bacterial community composition and functions. Therefore, the interaction among ARGs, the bacterial community, bacterial functions, and pollutant accumulations in the CW-MFC was complex. This study provides useful implications for the application of CW-MFCs for the treatment of wastewater contaminated with antibiotics and heavy metals.
锌（Zn）的持续积累对人工湿地-微生物燃料电池（CW-MFC）中抗生素抗性基因（ARGs）命运的影响尚不清楚。本研究采用三组 CW-MFC，考察了 Zn 添加和电路模式对抗生素去除、ARGs 出现、细菌群落和细菌功能的影响。结果表明，连续 Zn 暴露在初始阶段会富集目标 ARGs，而过量 Zn 积累会降低抗生素去除率和 ARGs 丰度。主成分分析表明，ARGs 和细菌群落分布特征受抗生素和 Zn 大量积累以及电路模式的显著影响。冗余分析、偏最小二乘路径建模和 Procrustes 分析表明，抗生素和 Zn 的积累、细菌群落的组成、电路模式以及与水平基因转移相关的 intI 的丰度共同导致了 ARGs 在电极和出水中的分布。此外，连续暴露于 Zn 会降低细菌多样性，并改变使用 PICRUSt 工具预测的细菌群落组成和功能。通过网络分析进一步揭示了 ARGs 的共现及其潜在宿主和细菌功能。变分分解分析还表明，目标污染物的积累和电路模式对细菌群落组成和功能有显著影响。因此，CW-MFC 中 ARGs、细菌群落、细菌功能和污染物积累之间的相互作用是复杂的。本研究为 CW-MFC 处理同时含有抗生素和重金属的废水提供了有用的启示。
