摘要
      厌氧发酵是处理废活性污泥（WAS）的有效方法，可以实现资源的产生和污染物的减少，通常采用各种预处理来提高其性能。这项工作主要研究了典型的WAS预处理方法对厌氧发酵过程中抗生素抗性基因（ARGs，作为新出现的污染物）去除的影响，并揭示了潜在的机制。结果表明，所有预处理策略对总ARGs的去除都表现出明显的影响，其顺序为Fe2+活化过硫酸盐（PS/Fe2+）>pH 10>超声波处理>加热，并对特定的ARGs（即易去除的（aadA1和sul1）和持久性ARGs）表现出选择性去除趋势。机理分析表明，预处理破坏了细胞外聚合物（EPS）并提高了细胞膜渗透性（尤其是PS/Fe2+和Heat）。然后，ARGs释放的增加有利于随后移动遗传元件（MGE）和细胞外ARGs（尤其是PS/Fe2+和pH10）的减少，导致ARGs衰减。预处理显著改变了微生物群落结构和潜在ARGs宿主（即硫酸菌和反硝化菌）的丰度。此外，不同的预处理对与ARGs增殖相关的微生物代谢特性（即ABC转运蛋白、双组分系统和细菌分泌系统）表现出不同的影响，这也有助于WAS发酵过程中ARGs的衰减。偏最小二乘路径建模（PLS-PM）分析表明，细菌群落（总效应=0.968）是决定ARGs命运的关键因素。
Abstract
Anaerobic fermentation is effective for waste activated sludge (WAS) disposal to realize resource generation and pollutants reduction, and various pretreatments were commonly applied to improve the performance. This work mainly investigated the effects of typical WAS pretreatment approaches on the antibiotic resistance genes (ARGs, as emerging contaminants) removal during anaerobic fermentation processes and unveiled the underlying mechanisms. The results indicated that all the pretreatment strategies exhibited evident effects on the overall ARGs removal with the order of Fe2+ activated persulfate (PS/Fe2+) > pH 10 > Ultrasonication > Heat, and showed selective removal tendency for the specific ARGs (namely easily removed (aadA1 and sul1) and persistent ARGs). Mechanistic analysis demonstrated that the pretreatments disrupted the extracellular polymeric substances (EPS) and rose the cell membrane permeability (particularly for PS/Fe2+ and Heat). Then the increased ARGs release benefitted the subsequent reduction of mobile genetic elements (MGEs) and extracellular ARGs (especially for PS/Fe2+ and pH10), resulting the ARGs attenuation. Pretreatments significantly shifted the microbial community structure and the abundances of potential ARGs hosts (i.e., Sulfuritalea, and Denitratisoma). Also, the different pretreatments exhibited distinct effects on the microbial metabolic traits related with ARGs proliferation (i.e., ABC transporters, two-component system and bacterial secretion systems), which also contributed to the ARGs attenuations during WAS fermentation. The partial least-squares path modeling (PLS-PM) analysis indicated that the bacterial community (total effects = 0.968) was key factor determining ARGs fates.

https://www.sciencedirect.com/science/article/abs/pii/S0013935122020941