中文摘要：

研究反硝化除磷菌（denitrifying polyphosphate-accumulating organism,DPAO）的筛选、鉴定及反硝化功能基因. 利用反硝化培养基分离得到菌株ZQN2,经好氧吸磷试验,硝酸盐还原产气试验并辅助异染颗粒和PHB颗粒染色,确定其为反硝化除磷菌. 厌氧释磷/缺氧吸磷试验结果表明,菌株ZQN2在厌氧段释磷并合成PHB（poly-β-hydroxybutyrate）,在缺氧段以NO3-为电子受体氧化PHB并过量吸磷,进行了同步反硝化除磷. 对菌株ZQN2进行16S rRNA基因序列分析,并构建系统进化树,结果表明该菌株与GenBank数据库中多株Bacillus cereus菌株16S rRNA基因的同源性在99%以上. 结合生理生化检测,判断菌株ZQN2为蜡状芽胞杆菌（Bacillus cereus）. 对其反硝化功能基因的研究表明,菌株ZQN2为nirS＋和nirK-型,从分子生物学角度确认其具有反硝化功能; 菌株ZQN2的nirS序列的系统发育分析结果表明,其nirS序列与多株Pseadomonas aeruginosa的亲缘关系最接近,这与基于16S rRNA的系统发育分析的结果不一致.

英文摘要：

A denitrifying polyphosphate-accumulating organism （DPAO） was isolated and identified, and the denitrifying functional genes were investigated. The strain ZQN2 was isolated using denitrifying medium. It was distinguished as DPAO by tests of aerobic phosphorus uptake, nitrate reduction, metachromatic granules and PHB （poly-β-hydroxybutyrate） granules dyeing. Test of anaerobic phosphorus release/anoxic phosphorus uptake showed that strain ZQN2 released phosphorus and synthesized PHB at the anaerobic phase and used NO3- as acceptor to oxidize PHB during the anoxic phase with luxury phosphorus uptake, performing the function of simultaneous denitrifying phosphorus removal. The 16S rRNA gene sequence of strain ZQN2 was used for homology analysis and construction of phylogenetic trees. The results suggested that the 16S rRNA gene sequence of ZQN2 had up to 99% homology with those of many strains of Bacillus cereus strains in GenBank database. With physiological and biochemical reactions, the strain ZQN2 was identified as Bacillus cereus. The result of denitrifying functional gene study suggested that strain ZQN2 was the type of nirS＋ and nirK-, which confirmed its denitrifying function from molecular biology point of view. Moreover, the phylogenetic analysis of nirS gene of ZQN2 showed that it was closely related to many strains of Pseadomonas aeruginosa, which was different from the analysis results of the 16S rRNA.