Screening And Antimicrobial Activity Of Moderate Halophiles From The Daishan Solar

The aim of this study was to investigate the potential antimicrobial activities of moderately halophiles from solar saltern. A total of 106 halophilic strains were isolated from the soil of Daishan solar saltern by culture-dependent method based on RM medium. All the isolated strains were tested for their antimicrobial activity using the inhibition-zone method. The phylogenetic position of strains was determined by16 S rRNA sequencing. Our results showed that among 106 strains tested, 27 strains showed remarkable activities against Gram-positive bacterium, Gram-negative bacterium and human pathogenic fungi. Phylogenetic analysis indicated that 27 strains belonged to seven genera, Halomonas, Halobacillus, Marinobacter,Microbulbifer, Piscibacillus, Bacillus and Virgibacillus.The identification of the strain ZSTB203 was determined by morphological characteristics, physiological tests and phylogenetic analysis based on 16 S rRNA sequence comparison. The results showed that ZSTB203 strain is Gram-positive, rod in shape, containing spores and no lipid particles. Phylogenetic analysis showed that the strain was closely related to the member of Halobacillus faecis NBRC103569,with which they shared 99.7% similarity. The optimum condition for ZSTB203 growth was NaCl 10g/L, temperature 30℃ and pH 7. 0.The antimicrobial active compounds produced by ZSTB203 strain was detected.Twenty components were primary isolated and purificated from the ZSTB203 culture filtrates by chromatographic column and HPLC, and the 14# component had antimicrobial activity by the inhibition tests. The analytical methods of ZSTB203,LC-MS, UV,were applied to identify the 14# active compounds. The LC-MS showed that the 14# component contains twenty-two compounds, whose molecular weights were 530.4, 583.4, 581.4, 770.4, 538.4, 242.4, 1048.7, 756.4, 273.4, 301.4, 351.4,317.4, 278.2, 331.5, 148.3, 279.4, 255.4, 281.4, 283.5, 428.3, 303.5, 365.4respectively. The results of UV indicated that the active compounds might contain-OH、-NH2、-S.