一株中度嗜盐菌的分离及生物学特性

Isolation and Characteristics of a Moderately Halophilic Bacterium

从我国内蒙古吉兰泰盐湖的样品中分离得到一株中度嗜盐细菌菌株JLT-01,研究了其形态和特性.结果显示：该菌株为杆状,革兰氏阴性,无芽孢,无荚膜,无鞭毛;最适培养温度为30℃,最适生长pH值7.5,最适生长盐度10%~12%（m/V）,最适生长Mg2＋浓度3.0%（m/V）;能利用葡萄糖、蔗糖、半乳糖作为唯一碳源生长.脂肪酸成分分析表明在JLT-01中主要脂肪酸为C16：0与C18：1ω9c,含量分别为26.39%和20.30%.Tm法测定该菌的（G＋C）含量（摩尔分数）为52.3%.以该菌的16S rRNA基因序列为基础构建了系统发育树;16S rRNA基因序列的序列同源性比对表明该菌与海杆菌属Marinobacter lipolyticus SM19T的同源性为98.0%,与Marinobacter属内其它菌株的同源性在96.0%~99.0%之间.DNA-DNA杂交实验分析显示：JLT-01与M.lipolyticus DSM15157的杂交率小于70%.结果表明,菌株JLT-01是海杆菌属的一个新菌株.

A Gram-negative,rod-shaped,non-motile,non-spore-forming and moderately halophilic bacterium（strain JLT01） was isolated from a sediment sample of Jilantai salt lake in Inner Mongolia,China.The strain grew optimally at 30 ℃,pH 7.5,10%~12%（m/V） NaCl and 3.0%（m/V） Mg2＋.The strain JLT-01 used glucose,sucrose,galactose as carbon and energy sources.The contents of the two major cellular fatty acids,C16：0 and C18：1ω9c,were 26.39% and 20.30% of the total fatty acids,respectively.The genomic DNA（G＋C） content was 52.3%（mole fraction）.Phylogeneticanalysis based on the 16S rRNA gene sequence revealed that strainJLT-01 was closely related to Marinobacter lipolyticus SM19T（98.0% sequence similarity） and other recognized species withinthe genus Marinobacter（96.0%~99.0%）.The level of DNA–DNArelatedness between strain JLT-01 and M.lipolyticus DSM15157 wasless than 70%.Based on the phenotypic and genotypic data presented,strain JLT-01 was considered to represent a new strain of thegenus Marinobacter.