关键词: 中度嗜盐菌, 鉴定, 达坂喜盐芽孢杆菌, 抗菌活性

Abstract: 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 16S rRNA 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 Halobacillus dabanensis strain N522 based on 16S rRNA sequence comparison and physiological and biochemical tests. The strain N522 belonged to moderately halophilic bacterium due to its optimal growth concentration of NaCl was 100 g/L，and pH 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 kD to 5 kD. Moreover，the antimicrobial peptides were resistant against pH 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.

Key words: moderately halophilic bacterium, identification, Halobacillus dabanensis, antimicrobial activity