摘要

    锌（Zn）的持续积累对人工湿地微生物燃料电池（CW-MFCs）中的抗生素抗性基因（ARGs）命运的影响尚不清楚。在这项研究中，在三组连续波MFC中研究了添加锌和电路模式对抗生素去除，ARG的发生，细菌群落和细菌功能的影响。结果表明，连续的锌暴露在初始阶段丰富了目标ARGs，而过量的Zn积累降低了抗生素的去除和ARGs的丰度。主成分分析表明，ARGs和细菌群落分布特征受到抗生素和Zn的大量积累以及电路模式的显着影响。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的丰度共同促进了ARGs的分布在电极和废水中。此外，连续暴露于锌会降低细菌多样性，并改变使用PICRUSt工具预测的细菌群落的组成和功能。使用网络分析进一步揭示了ARGs，其潜在宿主和细菌功能的共存。变异分区分析还表明，目标污染物的积累和电路模式对细菌群落的组成和功能有重大影响。因此，CW-MFC中ARG，细菌群落，细菌功能和污染物积累之间的相互作用非常复杂。这项研究为CW-MFCs在处理被抗生素和重金属污染的废水中的应用提供了有益的启示。

    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.

    https://www.sciencedirect.com/science/article/abs/pii/S0269749120328098