一株好氧反硝化细菌的分离鉴定及反硝化能力

Identification and phylogenetic analysis of an isolated aerobic denitrifier

利用驯化活性污泥的方法筛选出一株好氧反硝化细菌G3，该菌在碳源充足且溶解氧为（4．0±1．0）mg·L^-1条件下，24h内对NO2^- -N积累量为12．03mg·L^-1，对N03^- -N的去除率为91．09％．扫描电镜观察其形态特征为（0．4-0．6）μm×（1．2-2．0）μm的短杆菌．16SrDNA序列分析表明．该菌与Pseudomonas stutzeri的相似性为100％．利用MEGA软件对该菌株与已报道的相关微生物进行系统发育分析，并克隆出与好氧反硝化相关的周质硝酸盐还原酶的亚基napA基因，初步判定筛选菌株具有周质硝酸盐还原酶．

By domesticating activated sludge in a SBR reactor with alternation of anaerobic/aerobic processes, the bacterium Pseudomonas stutzeri strain G3 was isolated, which is capable of aerobic denitrification with sodium succinite as sole carbon source. When the concentration of dissolved oxygen was （4.0±1.0）mg·L^-1,the nitrite accumulation and the removal rate of nitrate by strain G3 were 12.03 mg·L^-1 and 91.09% in 24 hours, respectively; when C/N = 3 the removal rate of nitrate by the bacterium cultured at 30℃ for 28 h was 72.91%. The morphology of the bacterium was a brevibacillus with average size of （0.4-0.6） μm×（1.2 - 2.0） μm as measured by scanning electron microscopy. Phylogenetic analysis based on partial 16SrDNA and performed by MEGA showed that G3 has 100% sequence similarity with Pseudomonas stutzeri. The phylogenetic tree of the strain and its neighboring denitrifiers is given. Its partial napA gene was cloned, and shown to be a subunit of periplasmic nitrate reductase （ NAR）, which is considered to be related to aerobic denitrification.