摘要
      热水解预处理（THP）可以有效地去除污泥中的抗生素抗性基因（ARGs），但在随后的厌氧发酵中经常观察到反弹效应。本研究的目的是阐明细胞内和细胞外ARG（iARGs和eARGs）在污泥产酸发酵过程中与THP偶联的分布和命运。我们的研究结果表明，在实际条件下（140°C，30分钟），THP显著降低了原污泥中总ARG的绝对丰度，但使eARGs增加了0.3–1.4个对数单位。两个接收生污泥和水解污泥的产酸发酵罐对总ARG的去除没有显著差异，其中iARGs在产生的生物固体中占主导地位。观察了细菌群落的演替以及ARG类型、可移动遗传元件和细菌分类群之间的共生关系，为发酵污泥中iARGs模式提供了系统发育基础。然而，eARGs易被生物降解，半衰期为2.34小时，并且它们通过转化对ARGs的传播贡献有限。这些发现表明，在污泥的产酸发酵过程中，重点是缓解iARGs，这可以通过降低潜在宿主的丰富度和物理化学破坏来实现。
Abstract
Thermal hydrolysis pretreatment (THP) can effectively remove the antibiotic resistance genes (ARGs) from sewage sludge, but the rebounding effects in the subsequent anaerobic fermentation are often observed. The purpose of this study was to elucidate the distribution and fate of intracellular and extracellular ARGs (iARGs and eARGs) in the sludge acidogenic fermentation process coupled with THP. Our results revealed that THP significantly reduced the absolute abundance of total ARGs in raw sludge but increased eARGs by 0.3–1.4 log units under practical conditions (140 °C for 30 min). There is no significant difference in the removal of total ARGs between the two acidogenic fermenters receiving raw and hydrolyzed sludge, with iARGs prevailing in the produced biosolids. The succession of bacterial community and the co-occurrence relationships among ARG type, mobile genetic elements and bacterial taxa were observed, suggesting a phylogenetic basis for the iARGs patterns in fermented sludge. However, eARGs were susceptible to biodegradation with a half-life of 2.34 h and they contributed limitedly to the ARGs propagation through transformation. These findings suggest an emphasis on the mitigation of iARGs during the acidogenic fermentation of sludge, which would be achieved by lowering the richness and physicochemical destruction of potential hosts.

https://www.sciencedirect.com/science/article/abs/pii/S0043135421010708