Hoh Xil, an extremophile environment situated at the Yushu Tibetan Autonomous Region in southwest Qinghai, is one of the most primitive and well-preserved natural environment on earth. The microbial diversity in this area is poorly known till date. In this present study an attempt has been made to selectively isolate the alkalophilic microorganisms in 12 salina soil samples from Hoh Xil, by using five different medium. As a result, 5 alkaliphilic or salkaline tolerant isolates were obtained. 16S rRNA gene sequence analysis showed that 4 strains belonged to 4 different genera, such as Planomicrobium, Kocuria, Aerococcus, and Bacillus. Another strain, designated CPCC 100153 was the nearest to thegenus Geomicrobium, showing the 16S rRNA gene sequence similarity level of 93.5 % to the strain Geomicrobium hahphilum BH1T. Based on the phenotypic characteristics, physiological and biochemical tests, chemotaxonomic analysis and genotypic data, we found that the strain CPCC 100153T not only shared some common characteristics with the alkaliphilic or salkaline tolerant species of the related genus in the family Bacillaceae but also clearly differentiated from them. Therefore, we propose the strain CPCC I00153T represents a novel genus and species within the family Bacillaceae.%可可西里是位于青海玉树藏族自治州的自然环境保护区,由于当地的恶劣气候特点,其土壤微生物多样性很少被研究.采用5种分离培养基对来源于可可西里的12个盐碱土壤样品进行选择性分离,共分离得到5株细菌.其中4株菌分别属于游动微菌属(Planomicrobium)、库克菌属(Kocuria)、气球菌属(Aerococcus)和芽孢杆菌属(Bacillus);另有一株乳黄色的嗜碱耐盐细菌CPCC100153,其16S rRNA基因序列比对结果显示与最相近的地杆菌属(Geomicrobium)相似性仅为93.5％.综合分析CPCC 100153菌株的形态学、生理生化、化学分类特征、遗传与发育学特征等表型和基因型数据,该菌既与芽孢杆菌科内的相近分类单元的嗜碱菌有很多相似之处,也具有明显区别之处,可能为一个潜在的新属.
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