好氧-厌氧两相堆肥过程中抗生素耐药基因的变化特征及影响因素研究

Change Characteristics and Influencing Factors of Antibiotic Resistance Genes in Aerobic and Anaerobic Two-Phase Composting

针对堆肥处理过程中抗生素耐药基因(antibiotic resistance genes,ARGs)去除效率不高、诱导潜在致病菌传播扩散等环境安全问题,采用好氧-厌氧两相堆肥处理猪粪、秸秆,探讨ARGs丰度及微生物群落的变化特征,并明确影响ARGs相对丰度变化的关键因子.结果表明:与单一好氧相比,好氧-厌氧两相堆肥能更有效地降低部分ARGs及潜在致病菌的相对丰度,其中ermB、tetK的相对丰度分别降低了39.68%、72.19%,假单胞菌属(Pseudomonas)、梭菌属(Clostridium_sensu_stricto_1)的相对丰度分别降低了96.09%、90.07%.主成分分析(Principal Component Analysis,PCA)及冗余分析(Redundancy analysis,RDA)得出,微生物群落和环境因子均显著影响ARGs相对丰度的变化(P<0.05),贡献率分别为82.0%、71.2%.其中,梭菌属(Clostridium_sense_stricto_1)、黄杆菌属(Flavobacterium)、尿素芽孢杆菌属(Ureibacillus)和海洋杆菌属(Oceanobacillus)是影响ARGs相对丰度变化的主要微生物菌属;温度、电导率、含水率和pH是影响ARGs相对丰度变化的关键环境因子,贡献率分别为22.0%、16.7%、16.2%和15.0%.研究显示:与好氧堆肥相比,好氧-厌氧两相堆肥能更有效地去除ARGs,并抑制潜在致病菌的繁殖扩散,从而减少环境风险;然而部分ARGs和潜在致病菌仍存在增殖现象,因此亟需进一步优化好氧-厌氧两相堆肥工艺.

In view of the low removal inefficiency of antibiotic resistant genes or the spread of potential pathogens and other environmental safety issues in the course of composting,this research used aerobic and anaerobic two-phase composting to treat pig manure and straw to explore the change characteristics of antibiotic resistance genes(ARGs)abundance and microbial community,and identify the key factors influencing the relative abundance of ARGs.The results suggested that aerobic and anaerobic two-phase composting process could reduce the relative abundance of some ARGs and potential pathogens more effectively.Among them,the relative abundance of ermB,tetK and Pseudomonas,Clostridium_sensu_stricto_1 was reduced by 39.68%,72.19%and 96.09%,90.07%,respectively.Principal component analysis(PCA)and redundancy analysis(RDA)showed that microbial community and environmental factors significantly influenced the change of ARGs(P<0.05),contributing 82.0%and 71.2%,respectively.Clostridium_sense_stricto_1,Flavobacterium,Ureibacillus and Oceanobacillus were the main microbial genera that influenced the changes of the relative abundance of ARGs.Additionally,temperature,electrical conductivity,moisture content and pH were critical environmental variables,which could explain 22.0%,16.7%,16.2%and 15.0%of the variance of the relative abundance of ARGs,respectively.Those results indicated that compared with aerobic composting,aerobic and anaerobic two-phase composting could more effectively reduce the content of ARGs and inhibit the proliferation of potential pathogens,thereby reducing environmental risks.Because some ARGs and potential pathogens still proliferate,it is urgent to further optimize the aerobic and anaerobic two-phase composting process.