摘要
为了解在土霉素(oxytetracycline,OTC)胁迫下活性污泥中微生物的作用机制,以分别含0、0.1、5、20、60mg/L OTC人工废水的活性污泥为对象,应用聚丙烯酰胺凝胶电泳技术(denaturing gradient gel electrophoresis,DGGE)研究活性污泥微生物群落结构随不同废水OTC负荷及反应器运行时间的动态变化特点,并结合扫描电镜技术对活性污泥的形态进行观察.结果表明:在反应器运行过程中,对照组(未添加OTC)比处理组(添加不同质量浓度OTC)的活性污泥具有更丰富的微生物相.仅在对照组中发现了丝状菌;短杆菌在处理组中的比例明显降低,球状菌表现出更强的OTC适应性.在运行至88 d时,对照组和OTC质量浓度≤20 mg/L的处理组中均出现较多体型较大的球状微生物.活性污泥中主要优势菌属于变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes),但各菌属表现出不同的OTC抗性,在不同处理组间出现不同优势菌群,分别在其相应的废水处理中发挥着作用,从而使活性污泥的废水处理效率逐渐恢复.这些结果说明活性污泥微生物群落结构及其废水处理效率具有OTC质量浓度效应,OTC质量浓度越高,其受到的影响越大,同时,低浓度OTC的影响也会随着时间的延长越来越显著;但是,在长期OTC的选择作用下,微生物群落结构呈现动态变化,出现了适应OTC的新菌群,为活性污泥废水处理效率的回升带来了转机.
Oxytetracycline （OTC）, a broad-spectrum antibiotic, has been widely used in defense against infectious gram-positive and gram-negative bacteria that are pathogenic to livestock. As a result, OTC can be detected in various effluents, such as livestock wastewater, municipal sewage, and hospital wastewater, as well as their receiving environments. Activated sludge has played an important role in wastewater treatment for nearly one hundred years. However, the pervasiveness of OTC in modern waste streams reduces the viability of microorganisms in activated sludge which are inhibited by OTC. This study was carried out to investigate the interaction between wastewater treatment efficiency and the activity of microbial communities in activated sludge under long-term exposure to OTC. Sequencing batch reactors （SBRs） treating wastewater containing concentrations o{ 0, 0.1, 5, 20, 60 mg/L OTC were established and studied {or 88 days, respectively. All reactors were discharged of effluent every two days and thensupplied with a new batch of artificial wastewater. The performance of each reactor was determined by measuring pH, total nitrogen （TN） removal rate and concentration of chemical oxygen demand （COD） in the effluent. Denaturing gradient gel eleetrophoresis （IN3GE）, targeting the V6 - V7 region of 16S rRNA gene, was applied to analyze the variation in bacterial community structure in the activated sludge as influenced by different concentrations of OTC. Additionally, scanning electron microscopy （SEM） was employed to observe the morphology of activated sludge.
出处
《浙江大学学报（农业与生命科学版）》
CAS
CSCD
北大核心
2013年第5期545-555,共11页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
"十二五"国家科技支撑计划课题"东部河网水源污染地区村镇安全供水技术集成与示范"(2012BAJ25B07)
关键词
土霉素
活性污泥
扫描电镜
变性梯度凝胶电泳（DGGE）
微生物群落结构
oxytetracycline
activated sludge
scanning electron microscopy
DGGE （denaturing gradient gelelectrophoresis）
microbial community structure
