摘要

据报道，碱性发酵是从废污泥中回收有价值产物的有效方法。然而，迄今为止，碱性pH对污泥厌氧发酵期间抗生素抗性基因（ARG）的命运的潜在影响从未被记录。在这项研究中，当污泥在pH10厌氧发酵时，观察到污泥中的目标ARGs被有效和稳定地去除。与对照相比（没有pH调节），pH10下目标ARGs的丰度降低了0.87（sulI ），1.36（sulII），0.42（tet（O）），1.11（tet（Q）），0.79（tet（C））和1.04（tet（X））对数单位。进一步的调查表明，碱性发酵改变了潜在的ARGs寄主的群落结构。此外，碱性发酵显着降低了基因载体（质粒DNA，胞外DNA和噬菌体DNA）的数量和ARGs-具有的能力，这可能通过结合，转化和转导来限制ARG的转移。这些结果表明，基因宿主的移动组成和受限的基因转移潜能可能是在pH 10下ARG减毒的关键原因。

Alkaline fermentation has been reported to be an effective method to recover valuable products from waste sludge. However, to date, the potential effect of alkaline pH on the fate of antibiotic resistance genes (ARGs) during anaerobic fermentation of sludge has never been documented. In this study, the target ARGs in sludge was observed to be removed effectively and stably when sludge was anaerobically fermented at pH 10. Compared with the control (without pH adjustment), the abundances of target ARGs at pH 10 were reduced by 0.87 (sulI), 1.36 (sulII), 0.42 (tet(O)), 1.11 (tet(Q)), 0.79 (tet(C)) and 1.04 (tet(X)) log units. Further investigations revealed that alkaline fermentation shifted the community structures of potential ARGs hosts. Moreover, alkaline fermentation remarkably decreased the quantities and the ARGs-possessing ability of genetic vectors (plasmid DNA, extracellular DNA and phage DNA), which might limit the transfer of ARGs via conjugation, transformation and transduction. These results suggest that the shifted compositions of gene hosts and restricted gene transfer potential might be the critical reasons for the attenuation of ARGs at pH 10.

https://www.sciencedirect.com/science/article/pii/S0048969716326523