Bacillus alkalisediminis sp nov., an alkaliphilic and moderately halophilic bacterium isolated from sediment of extremely shallow soda ponds

Alkaliphilic strains characterized by optimal growth at pH 9.0 and 5% (w/v) NaCl designated K1-25(T) and H3-93 were isolated from extremely shallow soda ponds located in Hungary. Cells of both strains were Gram-stain-positive, non-motile, straight rods and formed central, ellipsoidal endospores with swollen sporangia. The isolates were aerobic, catalase-positive, oxidase-negative and contained a peptidoglycan of type A1 gamma based on meso-diaminopimelic acid. In both strains, menaquinone-7 (MK-7) was the predominant isoprenoid quinone and the major cellular fatty acids were anteiso-C-15:0 and iso-C-15:0. The DNA G+C contents of strains K1-25(T) and H3-93 were 39.0 and 36.3 mol%, respectively. 16S rRNA gene sequence-based phylogenetic analysis revealed 99.2% similarity between strains K1-25(T) and H3-93 and the novel isolates had the highest similarities to Bacillus akibai 1139(T) (97.8 and 98.3%, respectively), Bacillus wakoensis N-1(T) (97.0 and 97.4%), Bacillus okhensis Kh10-101(T) (97.1 and 97.4%) and Bacillus krulwichiae AM31D(T) (96.9 and 97.1%). DNA-DNA hybridization between our strains and the type strains of closely related Bacillus species was lower than 70%. Although DNA DNA hybridization between strains K1-25(T) and H3-93 was 27%, the phenotypic and chemotaxonomic data did not support the differentiation of these two strains into separate species. Therefore, they represent genomovars of a novel species, for which the name Bacillus alkalisediminis sp. nov. is proposed. The type strain is K1-25(T) (=DSM 21670(T) =NCAIM B02301(T)).