Fermentibacillus polygoni gen. nov., sp nov., an alkaliphile that reduces indigo dye

Facultatively alkaliphilic strains, designated as strains IEB3(T) and IEB14, were isolated as indigo reducing strains from a fermented Polygonum indigo (Polygonum tinctoriuM Lour) liquor sample prepared in our laboratory using a medium containing an indigo fermentation liquor as a sole substrate. The 16S rRNA gene sequence phylogeny and similarity suggested that strains IEB3(T) and IEB14 exhibit distinctive positions among the members of the genus Bacillus, and their closest neighbour was Bacillus nanhaiisediminis NH3(T) (similarity: 97.4%) among the species with validly published names. The 16S rRNA sequence of strain IEB3(T) was identical to that of strain IEB14. The cells of the isolates stained Gram-positive and were facultatively anaerobic, straight rods that were motile by a pair of subpolar flagella. Strains IEB3(T) and IEB14 grew at temperatures between 12 and 40 degrees C with optimum growth at 30-33 degrees C and in the range of pH 7.5-12. Menaquinone-7 (MK-7) was detected as the major isoprenoid quinone. The DNA G+C contents of strains IEB3(T) and IEB14 were 49.1 and 49.9 mol%, respectively. The whole-cell fatty acid profile mainly (>10%) consisted of iso-C-14:0, iso-C-15:0 and anteiso-C-15:0. DNA-DNA hybridization revealed a low relatedness value between strain IEB3(T) and the phylogenetically most closely related species, Bacillus nanhaiisediminis JCM 16507(T) (<7%). On the basis of phenotypic and chemotaxonomic characteristics and phylogenetic data, the isolates represent a novel species within a novel genus, for which the name Fermentibacillus polygoni gen. nov., sp. nov. is proposed. The type strain is IEB3(T) (=JCM 30817(T)=NCIMB 14984(T)).