Oceanobacillus indicireducens sp. nov., a facultative alkaliphile that reduces an indigo dye.

An indigo-reducing facultatively alkaliphilic and halophilic strain, designated strain A21(T), was isolated from a fermented Polygonum indigo (Polygonum tinctorium Lour.) liquor sample aged for 4 days prepared in a laboratory. 16S rRNA gene sequence phylogeny suggested that strain A21(T) was a member of the genus Oceanobacillus with the closest relative being the type strain of Oceanobacillus chironomi (similarity: 96.0 %). The cells of the isolate stained Gram-positive and were facultatively anaerobic straight rods that were motile by peritrichous flagella. The strain grew between 18 and 48 °C with optimum growth at 39 °C. It grew in the pH range of 7-12. It hydrolysed casein, gelatin and Tween 20 but not Tweens 40, 60 and 80, starch or DNA. No isoprenoid quinone was detected and the DNA G+C content was 39.7 mol%. The whole-cell fatty acid profile mainly consisted of iso-C15 : 0, anteiso-C15 : 0 and C16 : 0. DNA-DNA hybridization experiments with O. chironomi revealed 13 % relatedness. Owing to the differences in phenotypic and chemotaxonomic characteristics, and phylogenetic analyses based on 16S rRNA gene sequences and DNA-DNA relatedness data from reported Oceanobacillus species, the isolate merits classification as a representative of a novel species, for which the name Oceanobacillus indicireducens sp. nov. is proposed. The type strain is A21(T) ( = JCM 17251(T)  = NCIMB 14685(T)). The description of the genus Oceanobacillus is also emended.