Bacillus salsus sp. nov., a halophilic bacterium from a hypersaline lake

Abstract

A Gram-staining-positive, endospore-forming, rod-shaped, strictly aerobic, slightly halophilic bacterium, designated strain A24T, was isolated from the hypersaline lake Aran-Bidgol in Iran. Cells of strain A24T were motile rods and produced oval endospores at a terminal position in swollen sporangia. Strain A24T was catalase and oxidase positive. Growth occurred with between 0.5 and 7.5 % (w/v) NaCl and the isolate grew optimally at 3 % (v/w) NaCl. The optimum temperature and pH for growth were 35 °C and pH 8.0, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain A24T belonged to the genus Bacillus within the phylum Firmicutes and showed the closest phylogenetic similarity with the species Bacillus alkalitelluris BA288T (97.2 %), Bacillus herbersteinensis D-1,5aT (96.0 %) and Bacillus litoralis SW-211T (95.6 %). The G+C content of the genomic DNA of this strain was 35.9 mol%. The polar lipid pattern of strain A24T consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unknown phospholipids. The major cellular fatty acids of strain A24T were anteiso-C15 : 0 and iso-C15 : 0. The respiratory quinones were MK-7 (94 %) and MK-6 (4 %). The peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. All these features confirm the placement of isolate A24T within the genus Bacillus . DNA–DNA hybridization experiments revealed a relatedness of 8 % between strain A24T and Bacillus alkalitelluris IBRC-M 10596T, supporting its placement as a novel species. Phenotypic characteristics, phylogenetic analysis and DNA–DNA relatedness data suggest that this strain represents a novel species of the genus Bacillus , for which the name Bacillus salsus sp. nov. is proposed. The type strain is strain A24T ( = IBRC-M 10078 T = KCTC 13816T).