一株中度嗜盐芽孢杆菌(Bacillus sp. BZ-SZ-XJ39)的微生物学特性

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

摘要:

【目的】了解一株来自新疆盐碱湖的中度嗜盐菌(Bacillus sp. BZ-SZ-XJ39)的微生物学特性,为进一步阐明该菌独特的盐适应机制奠定基础。【方法】通过16S rRNA 基因序列分析、G+C mol%含量测定、细胞形态和菌落观察、培养条件确定、营养与生理生化指标测定以及细胞化学组分分析等描述该菌的生物特性。【结果】基于16S rRNA 基因序列的同源性和系统发育树分析,菌株BZ-SZ-XJ39 与Bacillus saliphilus 6AGT (序列相似性为97.5%),Bacillus daliensis DLS13T (96.5%),Bacillus luteus JC167T (96.2%),Bacillus chagannorensis CG-15^T (95.5%)和Bacillus agaradhaerens DSM8721^T (95.3%)有密切的亲缘关系。基因组DNA G+C 含量为44.4 mol%±1.2 mol% (T_m)。菌株BZ-SZ-XJ39 为好氧、短杆状、革兰氏阳性菌。菌落呈黄色、圆形凸起、表面光滑且边缘整齐。菌株生长盐度范围为0.5%–28% (最适8%),pH 范围为5.5–9.5 (最适pH 8.0),温度范围为4–41 ℃ (最适33 ℃)。菌株BZ-SZ-XJ39 合成的主要脂肪酸包括anteiso-C_15:0(50.2%)和anteiso-C_17:0 (16.3%)。合成极性脂为磷脂(PL)、磷脂酰乙醇胺(PE)、磷脂酰甘油(PG)、二磷脂酰甘油(DPG)和磺酸基异鼠李糖基二脂酰基甘油(SQDG)。呼吸醌类型为甲基萘醌(MK-7)。菌株BZ-SZ-XJ39 已经在中国普通微生物菌种保藏管理中心(CGMCC1.12936)和日本微生物菌种保藏中心(JCM30194)冻干保藏,在GenBank 中的序列注册号为KP456019。【结论】基于BZ-SZ-XJ39 菌株的遗传型、表型、生理生化以及化学组成特征,初步确定该菌为Bacillus 属中的一个新成员。研究将为探索生命在高盐环境中存在的本质提供新素材,也可为生物技术的潜在应用提供新视角。

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.