Halobacillus mangrovi sp nov., a moderately halophilic bacterium isolated from the black mangrove Avicennia germinans

A moderately halophilic, spore-forming, Gram-positive, short-rod-shaped bacterium, designated strain MS10(T), was isolated from the surface of leaves of the black mangrove Avicennia germinans and was subjected to a polyphasic taxonomic study. Strain MS10(T) was able to grow at NaCl concentrations in the range 5 - 20% (w/v) with optimum growth at 10% (w/v) NaCl. Growth occurred at temperatures of 10 - 50 degrees C (optimal growth at 33 - 35 degrees C and pH 6.0 - 9.0 (optimal growth at pH 7.0). Phylogenetic analysis based on 1 6S rRNA gene sequence comparisons revealed that strain MS10(T) fell within the branch encompassing members of the genus Halobacillus and was most closely related to Halobacillus dabanensis JCM 12772(T) (99.2% 16S rRNA gene sequence similarity). The DNA G+C content of strain MS10(T) was 45.7 mol%, the major respiratory isoprenoid quinone was MK-7 and the cell-wall pepticloglycan was of the L-Orn-D-Asp type, characteristics consistent with its affiliation to the genus Halobacillus. Strain MS10(T) showed a level of DNA - DNA hybridization with H. dabanensis JCM 12772(T) of 29% and levels below 70% were also obtained with respect to other recognized members of the genus Halobacillus. The major fatty acids of strain MS10(T) were iso-C-16:0, anteiso-C-15:0, iso-C-14:0 and iso-C-15:0. Overall, the phenotypic, genotypic and phylogenetic results presented in this study demonstrate that strain MS10(T) represents a novel species of the genus Halobacillus, for which the name Halobacillus mangrovi sp. nov. is proposed. The type strain is MS10(T) (=CECT 7206(T)=CCM 7397(T)).