Swine manure contained high amounts of antibiotic resistance genes (ARGs) due to the antibiotics used in the feed,and thus,was commonly considered as a significant reservoir of ARGs.Anaerobic digestion (AD) was widely used for the resource utilization of swine manure,while it could further reduce the ARGs.This study investigated the enhancement of ARGs reduction through the addition of zero valent iron (ZVI),natural zeolite and Dnase along with mesophilic (mAD) and thermophilic digestion (tAD) being compared.Results showed that AD could realize the ARGs reduction with tAD superior to mAD,and ZVI and natural zeolite addition could further enhance the reduction,especially for the natural zeolite addition at mAD,while Dnase addition deteriorated the reduction.The changes of microbial community (MC),intI1,heavy metal resistance genes (MRGs) and virulence factors (VFs) were also followed to find the potential drivers of the variation of the ARGs reduction between treatments.MRGs were also reduced significantly,while intI1 changed little in mAD and decreased a lot in tAD.VFs varied each other,eaeA (Escherichia coli) was enriched significantly while asal (Enterococci) reduced in every treatment.Network analysis along with partial redundancy analysis indicated that the driver to the changes of ARGs between treatments varied each other with MRGs contributing the most followed by MC.
Antibiotic resistance genes swine manure anaerobic digestion mcr-1 heavy metal resistance genes
Junya Zhang Qianwen Sui Xiaoshan Meng Ziyue Wang Li Yao Rui Wang Dawei Yu Yawei Wang Meixue Chen Yuxiu Zhang Changping Zhang Yuansong Wei
State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;University of Chinese Academy of Sciences, Beijing 100049, China