一株嗜酸硫氧化菌的分离

从江西德兴分离得到一株嗜酸硫氧化杆菌DX-2,采用双层固体培养基进行分离纯化,对分离菌株进行了形态、生理生化特性研究及16SrRNA序列分析.该菌株为革兰氏阴性细菌,短杆状,菌体大小（0.4～0.5）μm×（1～2）μm,化能自养,可利用硫磺和硫代硫酸盐为能源生长,不能利用亚铁进行生长.以16SrRNA序列同源性为基础构建了相关种属在内的系统发育树,结果表明,DX-2与喜温硫杆菌（Acidithiobacillus caldus）处于同一进化树分支中,相似性达99%以上.考察了不同重金属离子对DX-2的生长的影响.

Isolation of an Acidophilic Sulfur Oxidizing Bacterium

An acidophilic sulfur-oxidizing bacterium DX-2 was isolated from Dexing area, Jiangxi province in China using enrichment medium and then purified on overlaid solid medium. The morphological, biochemical and physiological characters of DX-2 were studied. The cells of the strain DX-2 were Gram negative and rod-shaped (0.4～0.5) μm by (1～2) μm. The strain was capable of growth by using elemental sulfur or sodium thiosulfate as the sole energy sources. The strain was unable to oxidize ferrous iron. A phylogenetic tree was constructed by comparing published 16S rRNA sequences of the relative bacteria species. In the phylogenetic tree, DX-2 was the closest relative to Acidithiobacillus caldus with more than 99% sequence similarity. The effect of different heavy metals (Cu2+, Cr3+, Cd2+, Sn2+, Pb2+) on growth inhibition of DX-2was investigated.