中文摘要：

从水源水库沉积物中筛选出一株具有较高脱氮效率的异养硝化-好氧反硝化菌SF9。扫描电镜观察其形态特征为（0.2-0.4）μm×（0.4-0.8）μm椭球状,16S rDNA序列分析表明菌株与Delftia lacustris DSM 21246（T）相似性为100%,并分析其系统发育分类地位,对该菌进行贫营养反硝化特性研究。结果表明,该菌在分别以硝氮、亚硝氮及氨氮为唯一氮源时去除率分别达81%、64%和40%。同步硝化反硝化研究表明,该菌在氨氮存在的情况下会优先利用氨氮,在以氨氮与硝氮为氮源时和以氨氮与亚硝氮为氮源时氨氮的去除率分别达81%和74%。将菌株接种到微污染源水（总氮2.34mg/L、C/N为1.2）水体中,总氮72 h去除率达到35%,TOC消耗30%。结果表明,菌株SF9与其他已报道的好氧反硝化菌相比,能耐受更低的C/N比,可作为微污染水源水微生物修复的高效菌剂。

英文摘要：

An oligotrophic heterotrophic nitrification and aerobic denitrification bacteria named SF9 was isolated from the sediment of water supply reservoir. The morphology of the bacteria was ellipsoid with average size of（ 0. 2—0. 4） μm ×（ 0. 4—0. 8） μm as measured by scanning electron microscopy（ SEM）. This isolate was identified as Delftia lacustris DSM 21246（ T）（ 100% similarity）,and certified as Delftia lacustris by 16 S r DNA sequencing. Studies on denitrification characteristics under oligotrophic conditions revealed that the nitrogen removal rates were 81%,64% and 40%,using nitrate,nitrite and ammonia as sole nitrogen source,respectively. The isolate was cultured in simultaneous nitrification and denitrification medium,and the results showed that the bacteria in the case of ammonia nitrogen would give priority to the use of ammonia nitrogen; the ammonia nitrogen removal rate was 81% with ammonia and nitrate as nitrogen source and 74% with ammonia and nitrite as nitrogen source. Inoculated in the source water（ TN was 2. 34 mg/L,C/N ratio was 1. 2） for 72 h and the removal rate of TN was 35%,which suggested that the stain SF9 had more tolerance to a lower C/N ratio than that of the reported aerobic denitrifiers. It is therefore confirmed that the stain SF9 could be used as an efficient agent for micro-polluted source water bioremediation process.