高温强化牛粪高浓度厌氧发酵协同抗生素抗性基因削减

High-temperature Intensified High-concentration Anaerobic Fermentation of Cow Manure Synergizes with the Reduction of Antibiotic Resistance Genes

为提高畜禽粪便厌氧发酵(anaerobic digestion, AD)效率并促进其在高有机负荷条件下稳定运行,探究厌氧发酵过程中抗生素抗性基因(antibiotic resistance genes, ARGs)的消长机制。通过序批式试验研究了中温35℃和高温55℃对牛粪高浓度(12%TS)厌氧发酵产气性能、功能微生物群落及ARGs消长的影响,挖掘不同因子与ARGs的相互关系;实验证明:牛粪高固浓度发酵系统在高温55℃条件下具有更好的产气性能,甲烷产量提高17.27%。中温发酵过程VFAs的组分主要为乙酸和丙酸,二者约占VFAs的55.58%,其中丙酸积累量高,转化慢,系统出现短暂酸化状态。而高温发酵体系的稳定性及抗酸能力更强,高温改变了发酵过程中的优势细菌属,增加了Acetivibrio、Petrimonas、Methanothermobacter等微生物的丰度从而增加产气量,维持了产酸菌和产甲烷菌的动态平衡。相比中温(35℃),高温(55℃)发酵更能促进ARGs(尤其是aph(6)-Id、aph(3″)-Ib和sul1)相对丰度的削减。提高温度可显著提高厌氧发酵体系的产气性能,增加稳定性;微生物群落变化是ARGs消长的主要驱动因子。该研究结果可为畜禽养殖粪污厌氧发酵的工艺优化提供参考。

In order to improve the efficiency of anaerobic digestion(AD)of livestock and poultry manure and promote its stable operation under high organic load conditions,the growth and decline mechanism of antibiotic resistance genes(ARGs)during the anaerobic fermentation process was explored through sequencing;A batch experiment was carried out to study the effects of the gas production performance,functional microbial communities and ARGs of high-concentration anaerobic fermentation of cow manure(12%TS)at two process temperatures of medium temperature 35℃and high temperature 55℃,and explore the relationship between different factors and ARGs;The cow dung high solid concentration fermentation system has better gas production performance at high temperature of 55℃,and the methane production increases by 17.27%.The main components of VFAs during medium-temperature fermentation are acetic acid and propionic acid,which account for approximately 55.58%of VFAs.Among them,the accumulation of propionic acid is high,the conversion is slow,and the system is temporarily acidified.The high-temperature fermentation system has stronger stability and acid resistance.High temperature changes the dominant bacterial genera during the fermentation process,increases the abundance of Acetivibrio,Petrimonas,Methanothermobacter and other microorganisms,thereby increasing gas production and maintaining the dynamic balance of acidogenic bacteria and methanogenic bacteria.Compared with medium temperature(35℃),high temperature(55℃)fermentation can promote the reduction of the relative abundance of ARGs(especially aph(6)-Id,aph(3″)-Ib and sul1);Increasing the temperature can significantly improve the gas production performance of the anaerobic fermentation system and increase stability;Changes in the microbial community are the main driving factors for the growth and decline of ARGs.The research results can provide reference for process optimization of anaerobic fermentation of livestock and poultry breeding manure.