摘要
      废水处理厂的活性污泥含有非常高多样性的微生物和病毒，其中后者通过感染和细胞裂解来控制微生物动力学和代谢。然而，人们对病毒如何影响活性污泥的生化过程，例如在处理效率和污染物去除方面，仍知之甚少。本研究使用宏基因组和宏转录组深度测序，从三个传统污水处理厂的活性污泥样本中回收了数千个病毒序列。基因共享网络表明，大多数病毒不能被分配到已知的病毒属，这意味着活性污泥是新病毒和病毒多样性的一个未充分开发的库。对病毒-宿主联系的计算机预测表明，受感染的微生物宿主（主要属于细菌）具有转录活性，能够水解包括淀粉、纤维素和蛋白质在内的聚合物。一些病毒编码参与碳、氮和硫循环的辅助代谢基因（AMG），以及对多种药物产生耐药性的抗生素耐药性基因（ARGs）。病毒编码的AMG可以增强淀粉和纤维素等污染物的生物降解，这表明病毒在增强活性污泥的性能方面发挥着积极作用。然而，ARGs将使用病毒作为基因穿梭物传播给不同的微生物，这表明病毒有可能促进抗生素耐药性在环境中的传播。总的来说，这项研究强调了污水处理厂中病毒的混合作用，并破译了它们如何操纵活性污泥中的生化过程，对环境保护和生态系统安全都有影响。
Abstract
Activated sludge of wastewater treatment plants harbors a very high diversity of both microorganisms and viruses, wherein the latter control microbial dynamics and metabolisms by infection and lysis of cells. However, it remains poorly understood how viruses impact the biochemical processes of activated sludge, for example in terms of treatment efficiency and pollutant removal. Using metagenomic and metatranscriptomic deep sequencing, the present study recovered thousands of viral sequences from activated sludge samples of three conventional wastewater treatment plants. Gene-sharing network indicated that most of viruses could not be assigned to known viral genera, implying activated sludge as an underexplored reservoir for new viruses and viral diversity. In silico predictions of virus-host linkages demonstrated that infected microbial hosts, mostly belonging to bacteria, were transcriptionally active and able to hydrolyze polymers including starches, celluloses, and proteins. Some viruses encode auxiliary metabolic genes (AMGs) involved in carbon, nitrogen, and sulfur cycling, and antibiotic resistance genes (ARGs) for resistance to multiple drugs. The virus-encoded AMGs may enhance the biodegradation of contaminants like starches and celluloses, suggesting a positive role for viruses in strengthening the performance of activated sludge. However, ARGs would be disseminated to different microorganisms using viruses as gene shuttles, demonstrating the possibility for viruses to facilitate the spread of antibiotic resistance in the environment. Collectively, this study highlights the mixed blessing of viruses in wastewater treatment plants, and deciphers how they manipulate the biochemical processes in the activated sludge, with implications for both environmental protection and ecosystem security.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422002007