活性炭对城市有机固废厌氧消化过程抗生素抗性基因行为特征的影响

城市有机固废是抗生素抗性基因（antibiotic resistance genes，ARGs）的来源和储存库之一，其生物处理过程中ARGs的赋存变化规律需深入研究.采用定量PCR方法分析城市有机固废厌氧消化过程中多种类型ARGs和整合子基因的变化特征，探究了不同粒径的活性炭对目标基因行为特征的影响以及ARGs变化的潜在微生物机制.结果表明，无论是否添加活性炭，厌氧消化过程对初始体系中的总ARGs均具有削减作用，总ARGs绝对丰度的削减率为29.95%~63.40%.城市有机固废厌氧消化最终体系中，粉末活性炭（powered activated carbon，PAC）添加组中总ARGs丰度显著高于对照组（P<0.05），即PAC削弱了ARGs的削减效果，颗粒活性炭对ARGs变化无显著影响.厌氧消化过程中，ARGs的潜在宿主细菌主要属于梭菌纲（Clostridia）、拟杆菌纲（Bacteroidia）和互营养菌纲（Synergistia）.PAC添加时，潜在宿主细菌的富集是目标基因增殖的重要原因，且Clostridia可能是厌氧消化过程中ARGs消长的主要驱动因子.本研究结果将为了解城市有机固废厌氧消化过程中ARGs的转归特征以及外源添加活性炭对ARGs的影响机制提供参考.

Effects of Activated Carbon on the Fate of Antibiotic Resistance Genes During Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste

The organic fraction of municipal solid waste (OFMSW) has become one of the sources and reservoirs of antibiotic resistance genes (ARGs). It is essential to explore the fate of ARGs during biological treatment of OFMSW. Therefore, the changes in several types of ARGs and integron genes during anaerobic digestion of the OFMSW were analyzed by quantitative PCR. Furthermore, the effects of different particle sizes of activated carbon on the behaviors of the target genes and the potential microbial mechanisms of ARGs dynamics were investigated. The results showed that the total ARGs in the initial system were reduced after anaerobic digestion with or without the presence of activated carbon. The removal rate of the absolute abundance of total ARGs was 29.95%-63.40%. In the final system of anaerobic digestion of the OFMSW, the abundance of total ARGs in powdered activated carbon (PAC) groups was significantly higher than that in the control group (P<0.05). The supplementation of PAC inhibited the reduction of ARGs, and the supplementation of granular activated carbon had no significant effect on the change in ARGs. The potential host bacteria of ARGs were mainly Clostridia, Bacteroidia, and Synergistia during anaerobic digestion. The enrichment of host bacteria caused by PAC addition was the main reason for the increase in the target genes. Moreover, Clostridia might have been the main driving factor for the growth and decline of ARGs. These results will help us to understand the dissemination of ARGs and the impacts of activated carbon addition on ARGs during anaerobic digestion of the OFMSW.