一株亚硝酸盐降解菌的分离鉴定

为寻找对亚硝酸盐具有高效降解能力、稳定和安全的优良菌株，采用亚硝酸盐氧化细菌（Nitrite-oxidizing bacteria，NOB）富集、分离技术从湖州某水域淤泥中分离得到一株纯培养菌株N3，提取细菌的总DNA，利用细菌16S rDNA特异性引物进行多聚酶链反应（PCR）扩增；扩增产物经琼脂糖凝胶电泳和Sanger末端终止法测序分析，用NCBI—Blast软件将测序结果在Genbank等数据库中进行同源性检索。结果表明，N3的DNA扩增产物片断大小为1441bp，测序结果经检索证实N3与标准菌株Ceilulosimicrobium cellulans（AY665978．1）16S rDNA保守性片段有100％的同源性，可以判定所分离得到的N3菌株为纤维单胞菌属的纤维化纤维单胞菌（Cellulosimicrobium cellulans）。

Isolation and Identification of Nitrite-oxidizing Bacteria

In order to isolate good strains with high decomposition ability, stability and safety, a pare culture strain N3 was isolated from the sludge of a lake in Huzhou, Zhejiang, China by using nitrite-oxidizing bacteria （NOB） preconcentration and separation technique. Total DNAs of N3 was extracted and specific primers for 16S rDNA of nitrite oxidizer were used to conduct the amplification of polymerase chain reaction （PCR）. Amplified product was analyzed by agarose gel electrophoresis and Sanger sequencing. Homology analysis was made by searching in Genbank with NCBI-Blast. The amplified fragment of N3 was 1441 bp. 100% of N3 nucleotides were identical with a conserved fragment of a standard strain Cellulosimierobium cellulans （AY665978.1）. It is inferred that the isolated strain N3 belonged to Cellulosimicrobium cellulans.