一株中性嗜盐菌Halobacillus dabanensis N522的分离鉴定及其抗菌活性研究

Identification of a Moderately Halophilic Bacterium Halobacillus dabanensis N522 and Study of Its Antimicrobial Activity

从广东省徐闻盐场沉积物中分离嗜盐菌,鉴定目标菌株、考察培养条件,并对发酵液中抗菌活性物质进行理化性质研究。用稀释涂布法分离嗜盐菌,通过生理生化实验和16S r RNA基因序列分析鉴定分离得到的菌株;采用管碟法考察嗜盐菌发酵液的抗菌活性,并对其抗菌活性物质进行理化分析。结果显示,分离得到一株嗜盐菌,经生理生化实验和16S r RNA序列分析鉴定后命名为达坂喜盐芽胞杆菌(Halobacillus dabanensis)N522,其最适生长p H值和Na Cl浓度分别为7.0和100 g/L,属于中度嗜盐菌类群。菌株N522的发酵液对多种细菌和真菌具有抑制作用,其中,对金黄色葡萄球菌的抑制能力最强。经硫酸铵盐析和蛋白酶实验分析,初步确定菌株N522所产抗菌活性物质为多肽,分子量在3-5 k D之间,并且该抗菌活性物质对p H和温度稳定性良好。晒盐场沉积物中分离得到的中度嗜盐菌H.dabanensis N522可作为开发抗菌药物的潜在新来源。

The aims of this study are to isolate and identify halophilic bacteria from the sediments in Xuwen Solar Salt Field of Guangdong Province,to investigate the culture conditions of the target strain,and to study the physiochemical properties of active antimicrobial products in the fermentation. Serial dilution and plating method was employed to isolate halophilic bacteria from sediment samples. Then,the isolated strain was identified by physiological and biochemical experiment as well as 16 S r RNA gene sequence analysis. Further,the antimicrobial activity of the target strain fermentation broth was detected using several bacteria,yeasts and fungi by cylinder plate method,and the physicochemical property of antimicrobial materials was preliminarily studied. A halophilic bacterium was isolated and identified as Halobacill us dabanensis strain N522 based on 16 S r RNA sequence comparison and physiological and biochemical tests. The strain N522 belonged to moderately halophilic bacterium due to its optimal growth concentration of Na Cl was 100 g/L,and p H was 7.0. The fermentation broth of the strain inhibited the growth of several bacteria and fungi. Particularly,the strain showed the strongest antimicrobial activity to Staphylococcus aureus. The experiments of ammonium sulfate salting-out and protease degradation preliminarily revealed that the materials with antimicrobial activity in the broth of strain N522 was peptides,and its molecular weight was between 3 k D to 5 k D. Moreover,the antimicrobial peptides were resistant against p H and temperature. In conclusion,the moderately halophilic bacterium（H. dabanensis N522）isolated from the sediments of the Solar Salt Field may be developed as a potential new source for the novel antimicrobial medicines.