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Bacillus nakamurai sp. nov., a black-pigment-producing strain

Dunlap, Christopher A., Saunders, Lauren P., Schisler, David A., Leathers, Timothy D., Naeem, Naveed, Cohan, Frederick M., Rooney, Alejandro P.
International Journal of Systematic and Evolutionary Microbiology 2016 v.66 pp. 2987-2991
Two isolates of a Gram-stain-positive, strictly aerobic, motile, rod-shaped, endospore-forming bacterium were identified during a survey of the Bacillus diversity of the Agriculture Research Service Culture Collection. These strains were originally isolated from soil and have a phenotype of producing a dark pigment on tryptic soy agar. Phylogenetic analysis of the 16S rRNA gene indicated that these strains were related most closely to Bacillus subtilis subsp. inaquosorum (99.7% similarity) and Bacillus axarquiensis (99.7 %). In phenotypic characterization, the novel strains were found to grow between 17 and 50 _C and can tolerate up to 9% (w/v) NaCl. Furthermore, the strains grew in media of pH 5.5–10 (optimal growth at pH 7.0–8.0). The predominant cellular fatty acids were anteiso-C15 : 0 (34.8 %) and iso-C15 : 0 (21.9 %). The cell-wall peptidoglycan contained meso-diaminopimelic acid. A draft genome of both strains was completed. The DNA G+C content was 43.8 mol%. A phylogenomic analysis on the core genome of these two new strains and all members of the Bacillus subtilis group revealed these two strains formed a distinct monophyletic clade with the nearest neighbour Bacillus amyloliquefaciens. DNA–DNA relatedness studies using in silico DNA–DNA hybridizations showed the two strains were conspecific (93.8 %), while values with all other species (<31.5 %) were well below the species threshold of 70 %. Based on the consensus of phylogenetic and phenotypic analyses, these strains are considered to represent a novel species within the genus Bacillus, for which the name Bacillus nakamurai sp. nov. is proposed, with type strain NRRL B-41091T (=CCUG 68786T).