Genome-based reclassification of Bacillus okuhidensis as a later heterotypic synonym of Bacillus halodurans

The present study was carried out to clarify the taxonomic relationship between two closely related Bacillus species, Bacillus okuhidensis Li et al. 2002 and Bacillus halodurans (ex Boyer 1973) Nielsen et al. 1995. The maximum-likelihood tree based on the 16S rRNA gene sequence and the phylogenomic tree based on concatenation of 16 protein-marker genes showed that these species were similar. Average nucleotide identity (ANIm 99.25 %, ANIb 98.2 %) and digital DNA–DNA hybridization values (93.5 %) between B. okuhidensis DSM 13666T and B. halodurans DSM 497T were greater than the threshold values for bacterial species delineation, indicating that they belong to the same species. Therefore, B. okuhidensis Li et al. 2002 should be reclassified as a later heterotypic synonym of B. halodurans (ex Boyer 1973) Nielsen et al. 1995.