摘要
      污水处理厂是微塑料和抗生素抗性基因的重要汇点。关于污水处理厂功能模块之间的连接和在MP压力下ARG的传播的信息仍然缺乏。在本研究中，在聚苯乙烯（PS）MPs胁迫下，评估了序批式反应器（SBR）系统中P-、N-和C-相关功能基因与ARGs之间的相关性。在SBR的32个循环处理周期内，在0.5–50 mg L−1 PS MP胁迫下，出水中的总磷和化学需氧量（COD）没有显著变化，而0.5 mg L−2 PS MP影响氮循环过程。PS-MPs（0.5–50 mg L−1）促进了SBR中微生物群落的丰富性和多样性，反硝化过程旺盛。低剂量（0.5–5 mg L−1）的PS MP增强了细胞外聚合物的分泌，并促进了与C固定、C降解、P循环和N循环相关的功能基因的表达水平。同时，在低剂量PS-MPs胁迫下，aac（3）-II、blaTEM-1和tetW分别增加了27.13%、38.36%和9.57%；更重要的是，intI1的总绝对丰度几乎翻了一番。78.4%的这些P-、N-和C-相关的功能基因与intI1呈正相关，因此有利于ARGs的传播。本研究首次揭示了MPs胁迫下WWTP的功能模块与ARGs传播之间的潜在相关性。
Abstract
Wastewater treatment plants (WWTPs) are important sinks of microplastics (MPs) and antibiotics resistance genes (ARGs). Information regarding connections between functional modules of WWTPs and spread of ARGs under MPs stress is still lacking. In this study, correlations between P-, N-, and C-related functional genes and ARGs in a sequencing batch reactor (SBR) system were evaluated under polystyrene (PS) MPs stress. Total P and chemical oxygen demand (COD) in effluent showed no significant changes under 0.5–50 mg L−1 PS MPs stress within 32 cycle treatment periods of SBR, while 0.5 mg L−1 PS MPs affected the N cycling process. PS MPs (0.5–50 mg L−1) promoted the richness and diversity of microbial community in SBR, and the denitrification process was exuberant. PS MPs with a low dosage (0.5–5 mg L−1) enhanced secretion of extracellular polymeric substances and promoted expression levels of functional genes related to C fixation, C degradation, P cycling, and N cycling. Simultaneously, aac(3)-II, blaTEM-1, and tetW increased by 27.13%, 38.36%, and 9.57% under low dosages of PS MPs stress; more importantly, the total absolute abundance of intI1 nearly doubled. 78.4% of these P-, N-, and C-related functional genes were positively correlated with intI1, thus favoring transmission of ARGs. This study firstly disclosed the underlying correlations between functional modules of WWTPs and spread of ARGs under MPs stress.

https://www.sciencedirect.com/science/article/abs/pii/S0043135423003196