旨在从运城盐湖黑泥样品中分离获得一株耐盐细菌LAY，对其进行分类鉴定及抗菌特性研究。基于16S rRNA基因序列对菌株进行分类鉴定。以白色念珠菌为指示菌，采用杯碟法对菌株LAY发酵上清液进行抗菌活性检测，研究不同因素对其抗菌活性的影响；采用扫描电镜和透射电镜观察其抗菌效果，并对菌株基因组进行功能基因的PCR筛查。系统发育分析表明，菌株LAY为Bacillus属成员，为耐盐细菌。电镜观察发现，菌株LAY发酵上清液可导致白色念珠菌细胞结构出现明显异常。抗菌稳定性研究表明，菌株LAY发酵上清液活性较为稳定，表现出良好的对温度、pH、NaCl和紫外光的耐受性。功能基因筛查发现菌株LAY基因组中含有聚酮合酶（PKS）基因，表明该菌具有产聚酮类化合物的潜力。结果表明，盐湖环境中的极端微生物资源可作为抗菌活性物质的潜在新来源。%The goal of this work is to identify a halotolerant bacterium LAY isolated from Yuncheng Salt Lake and study its antimicrobial properties. The strain LAY was identified by 16S rRNA gene sequence analysis. Using Candida albicans as the indicator, the antimicrobial activity of the fermentation broth of strain LAY was detected by cylinder plate method, and meanwhile the effects of different factors on the activities were studied. Morphological and ultra-structural changes of treated cells were observed by scanning electron microscopy(SEM) and transmission electron microscopy(TEM). PCR screening of functional genes were also carried out. The results of phylogenetic analysis indicated that it was a halotolerant bacterium, and characterized as the genus of Bacillus, and named as Bacillus sp. LAY. The observation by electron spectroscopy discovered that morphological and ultra-structural changes of C. albicans after treatment by fermentation broth of Bacillus sp. LAY were significant. Antimicrobial properties of the strain LAY indicated that the activity of fermentation broth was stable, and showed excellent tolerance towards temperature, pH, NaCl and ultraviolet. Using specific primers, a gene for polyketide synthase(PKS)was detected by PCR technique, indicating that the strain LAY possessed the potential of producing polyketide. In conclusion, results from the study showed that extremophiles from salt lake might be developed as a potential new source of antimicrobial active substances.
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