萘降解菌的分离、鉴定及降解途径

Isolation and identification of naphthalene degrading bacteria and characterization of its degradation pathways

从武汉市金口张公堤处污泥富集分离出2株能以萘为唯一碳源生长的优势降解菌株XA1和XB1,经形态学观察、生理生化鉴定及16SrDNA测序分析,确定它们属于荧光假单胞菌(Pseudomonas fluorescens)。其最适生长温度均为28℃,最适生长pH分别为7.5和7.0。在最适生长条件下,菌株XA1、XB1以3%的接种量对500mg/L萘的降解率在第3天时分别达到了93.4%和74.7%。采用PCR和琼脂糖凝胶电泳技术检测到XA1、XB1中有儿茶酚2,3-双加氧酶基因(nahH)等萘降解过程中的关键酶基因,与NCBI中发布的基因序列相比较,相似度均达到99%。

Two strains,named as XA1 and XB1 utilizing naphthalene as the sole carbon source,were isolated from Zhanggong Dam of Jinkou in Wuhan City.XA1 and XB1were both identified as Pseudomonas fluorescens through morphological characterizations,physiological and biochemical identification and alignment analysis of the 16 SrDNA sequence.Their optimal growth temperature were both 28℃and the optimal growth pH value were 7.5and 7.0,respectively.When XA1 and XB1were inoculated in the liquid inorganic salts medium with naphthalene as the sole carbon source,the degradation rates of naphthalene after three days were 93.4% and 74.7%,respectively.Catechol 2,3-dioxygenase gene and some other genes were characterized with the PCR method and agarose gel electrophoresis.Results showed that sequences of catechol 2,3-dioxygenase gene and the others all possessed 99%similarity with the sequences in the NCBI