中国吐鲁番两株产木聚糖酶的极端耐碱Bacillus halodurans的分类鉴定

通过生理生化实验、16S rDNA序列分析和同源性杂交,将分离到的XJU-1和XJU-80菌种进行了分类鉴定。XJU-1和XJU-80具有较宽的pH生长范围(分别是pH4·5 ~12·6和pH3·8 ~12·6) ,其G C mol%含量分别是40·5mol%和42·2mol%。16S rDNA序列分析和DNA-DNA同源杂交结果表明,XJU-1和XJU-80与Bacillushalodurans C-125和Bacillus halodurans DSM497T具有较高的同源性(99 %) ;两者之间也具有85 %的相关性,但其与Bacillus halodurans C-125和Bacillus halodurans DSM497T分别具有81·3 %和71·5 %的相关性。基于以上结果,将两株分离菌株分类为Bacillus halodurans的两个新品系。

Isolation and identification of two xylanase-producing extremely alkali-tolerant strains of Bacillus halodurans from Turpan in China

Bacillus halodurans XJU-1 and XJU-80 were characterized in terms of physiological and biochemical characteristics, and 16S rDNA sequence homology and DNA-DNA hybridization analysis. The two isolates can grow in nutrient broth at a broad range of pH values from 4.5 to 12.6 for XJU-1 and from 3.8 to 12.8 for XJU-80, respectively. And the optimum temperature of growth were around 39 degrees C and 42 degrees C, respectively. Phylogenetic analysis of the two strains based on comparison of 16S rRNA sequence revealed that they are closely related to Bacillus halodurans C-125 and DSM497Twith 99% identity. DNA-DNA hybridization showed that the highest levels of DNA-DNA relatedness were found between the two strains (85%) and the B. halodurans type strains (81.3% and 71.5%), respectively. Moreover, the G + C content of the genomic DNA was 40.5 mol% for XJU-1 and 42.2 mol% for XJU-80.Our results demonstrate that strains XJU-1 and XJU-80 should be classified as two new members of the species B. halodurans.