Microbiological characteristics of a moderately halophilic bacterium, Bacillus sp. BZ-SZ-XJ39

Abstract:

[Objective] The aim of this study was to identify a moderately halophilic bacterium, strain BZ-SZ-XJ39, isolated from a saline-alkaline lake in Xinjiang Uyghur Autonomous Region of China. [Methods] On the basis of bacterial morphology and cultivation, biochemical characteristics, analysis of fatty acids, menaquinone and polar lipids, phylogenetic features of 16S rRNA gene sequence, and determination of (G+C) mol% content, the microbiological characteristics of strain BZ-SZ-XJ39 was described. [Results] Phylogenetic analysis based on 16S rRNA gene sequences shows that strain BZ-SZ-XJ39 represented a member of the genus Bacillus. Based on 16S rRNA gene sequence similarity analysis, the closest relatives were B. saliphilus 6AGT (sequence similarity 97.5%), B. daliensis DLS13^T (96.5%), B. luteus JC167^T (96.2%), B. chagannorensis CG-15^T (95.5%) and B. agaradhaerens DSM 8721T (95.3%). This isolate was Gram-staining-positive, non-motile and short rod-shaped. It had yellow colonies and grew with an optimum of 8% NaCl (range 0.5%–28%), at pH 8.0 (range pH 5.5–9.5), and at 33 ℃ (range 4–41 ℃). The dominant fatty acids were anteiso-C_15:0 (50.2%) and anteiso-C_17:0 (16.3%). The polar lipid patterns comprised phospholipid (PL), phosphatidyl ethanolamin (PE), phosphatidyl glycerol (PG), diphosphatidyl glycerol (DPG) and sulfo quinovosyl diacyl glycerol (SQDG) and the main respiratory quinones was Menaquinone 7 (MK-7). The genomic DNA G+C content was 44.4 mol%±1.2 mol% (T_m). The strain was designated as BZ-SZ-XJ39 (CGMCC1.12936, JCM30194). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain BZ-SZ-XJ39 is KP456019. [Conclusion] On the basis of phenotypic, chemotaxonomic and phylogenetic features, strain BZ-SZ-XJ39 could be a potential novel species within the genus Bacillus. This study will provide a new material of the boundaries for life under high-saline environmental conditions, and will also offer new insight into potential biotechnology applications.