高盐盐湖可分离嗜盐耐盐菌的种群多样性及四氢嘧啶产量评价

Population Diversity of Isolated Halophilic and Halotolerant Bacteria from Hypersaline Salt Lakes and Evaluation of Ectoine Production

为了解柴达木盆地茶卡盐湖、柯柯盐湖和小柴旦盐湖等三大硫酸镁亚型高盐盐湖可分离嗜盐耐盐菌的种群多样性,采用RM中、高盐培养基筛选分离可培养的嗜盐菌和耐盐菌,扩增16S rRNA基因序列进行种属鉴定和环境因子典范对应分析(CCA),选取优势菌属构建系统发育树,并采用高效液相色谱法(HPLC)检测次级代谢产物四氢嘧啶(Ectoine)积聚量,筛选高产菌株。结果表明三大盐湖共分离获得嗜盐和耐盐菌113株,优势种属为Bacillus(42株)、Staphylococcus(30株)和Halomonas(26株),各丰度与盐湖类型相关;其中中度嗜盐菌居多,其次为耐盐菌和弱嗜盐菌。系统发育分析表明Bacillus属存在5个进化分支,由6个种组成,Halomonas属存在6个进化分支,由7个种组成。HPLC检测四氢嘧啶积聚量,获得具有高产四氢嘧啶潜力菌株7株。这些研究结果说明柴达木盆地硫酸镁亚型高盐盐湖可分离嗜盐耐盐菌的优势菌属以Bacillus、Staphylococcus和Halomonas为主,且多为中度嗜盐菌,其高产四氢嘧啶的潜力菌株可用于后续四氢嘧啶发酵应用研究。

To fully understand the population diversity of isolated halophilic and halotolerant bacteria in the Chaka Salt Lake,Keke Salt Lake and Xiaochaidan Salt Lake of 3 major magnesium sulfate subtype hypersaline salt lakes,cultivable halophilic and halotolerant bacteria were screened in RM medium with medium and high salinity.The 16S rRNA gene sequences of the isolated strains were amplified for species identification and canonical correspondence analysis(CCA)of environmental factors.The dominant genera were selected to construct individual phylogenetic trees,and the accumulation of secondary metabolite ectoine was measured by high performance liquid chromatography(HPLC),and finally the strains with high-yield of ectoine were screened.Results showed that a total of 113 halophilic and halotolerant bacteria were isolated from the three major salt lakes.The dominant genera were Bacillus(42 strains),Staphylococcus(30 strains)and Halomonas(26 strains).Their abundance was related to the type of the salt lakes.The dominant genera Bacillus and Halomonas were mostly moderately halophilic bacteria,followed by halotolerant bacteria and weakly halophilic bacteria.Phylogenetic analysis demonstrated that Bacillus bacteria had 5 evolutionary branches,composed of 6 species,and Halomonas bacteria had 6 evolutionary branches,composed of 7 species.The accumulation of ectoine was detected by HPLC,and 7 strains with potential of high ectoine production were obtained.These results indicate that the dominant halophilic and halotolerant bacteria from the magnesium sulfate subtype hypersaline salt lakes in the Qaidam Basin are mainly Bacillus,Staphylococcus and Halomonas,and most of them are moderately halophilic bacteria.The strains with high ectoine production could be used for subsequent application research of ectoine fermentation.