摘要

    厌氧生物处理技术是抗生素抗性基因（ARG）的主要热点之一。以前的研究已经应用了电化学过程来提高沼气的产生，但是，高电压可能会促进膜的渗透性和活性氧的过度产生，从而促进ARGs的增殖，这是一个挑战。在此，研究了在0–0.9 V的梯度电压下，厌氧电化学膜生物反应器（AnEMBR）中的沼气产生和ARGs增殖。结果表明，随着应用量的增加，反应器性能（平均CH4产生和电流产生）得到明显改善。电压，并在0.9 V时达到最佳电压。但是，长期施加（> 30天）0.9 V会使反应堆性能下降。同时，与施加电压之前相比，在0.9 V下上清液和AnEMBR流出液中大多数目标ARG的相对丰度分别增加了0.68–1.55和0.42–1.26 log。断开电路连接后，这些ARG的丰度全部降低到原始水平。观察到intlI和ARGs之间存在显着相关性（例如tetA，tetQ，sulI和sulII），这表明水平基因转移可能有助于增加ARGs。此外，由施加电压引起的微生物群落的转移丰富了潜在的ARG-宿主（例如Tolumonas），从而促进了ARG的增殖。

    Anaerobic biological treatment technologies are one of the major hotspots of antibiotic resistance genes (ARGs). Previous studies have applied the electrochemical process to improve biogas production, however, it was challenged that high voltages might promote membrane permeability and reactive oxygen species overproduction to promote ARGs proliferation. Herein, the biogas production and ARGs proliferation in an anaerobic electrochemical membrane bioreactor (AnEMBR) were investigated at the gradient voltages of 0–0.9 V. Results show the reactor performances (average CH4 production and current generation) were distinctly improved with the increase of applied voltage, and reached the optimum at 0.9 V. However, long-term application (>30 day) of 0.9 V deteriorated the reactor performances. Meanwhile, the relative abundances of most target ARGs in the supernatant and effluent of AnEMBR at 0.9 V increased by 0.68–1.55 and 0.42–1.26 logs compared to those before applying voltage, respectively. After disconnecting the circuit, these ARGs abundances all decreased to the original level. Significant correlations between intlI and ARGs (e.g., tetA, tetQ, sulI, and sulII) were observed, indicating horizontal gene transfer may contribute to the increased ARGs. Moreover, the shift of microbial communities caused by the applied voltage enriched potential ARGs-hosts (e.g., Tolumonas), contributing to the proliferation of ARGs.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389421008293