中文摘要：

在生物脱氮过程中,好氧氨氧化细菌（ AOB）发挥重要作用.本研究通过梯度稀释培养、平板划线分离进行AOB分离纯化,获得两株氨氧化能力较强的AOB菌株A2和A7,它们能将培养液中的大部分氨氮氧化.对A2和A7菌株进行革兰氏染色,并通过光学显微镜及扫描电镜观察细胞形态,发现A2和A7均为革兰氏阴性菌,细胞呈杆状,长为1~1.5μm,宽约0.5μm.生理生化实验表明,A2和A7属于自养微生物,不能利用有机碳源.系统发育分析表明,A2和A7均为亚硝化单胞菌（ Nitrosomonas）.

英文摘要：

Aerobic ammonia_oxidizing bacteria （AOB） play important roles in biological nitrogen removal process. In this study,gradient dilution of domestication liquid and streak_ ing plate methods were used for AOB isolation and purification. Two strains of AOB,named A2 and A7,were obtained from culture medium,which contributed most ammonia oxida_ tion. After gram stain,detected by optical microscopy and scanning electron microscopy,A2 and A7 were both found as gram_negative and rod_shaped bacteria,with length of 1 ~1. 5 μm and width of 0. 5 μm. A2 and A7 were autotrophic microorganisms since organic car_ bon couldn’t be ultized. Phylogenetic analysis showed that the species of A2 and A7 were Nitrosomonas.