Description of Brachybacterium sillae sp. nov., a thermophilic bacterium isolated from a hot spring.

The taxonomic position of strain EF45031, isolated from the Neungam Carbonate hot spring, was examined using the polyphasic taxonomic approach. Strain EF45031 shared the highest percentage of 16S rRNA gene sequence with Brachybacterium nesterenkovii CIP 104813 (97.7%). The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between strain EF45031 and the type strains B. nesterenkovii CIP 104813 and B. phenoliresistens Phenol-A were 77.0%, 69.15%, 21.9% and 75.73%, 68.81%, 20.5%, respectively. Phylogenomic analysis using an up-to-date bacterial core gene (UBCG) set revealed that strain EF45031 belonged to the genus Brachybacterium. Growth occurred between 25 and 50 ℃ at pH 6.0-9.0 and could tolerate salinity up to 5% (w/v). Strain had anteiso-C and anteiso-C as major fatty acids. Menaquinone-7 (MK-7) was the predominant respiratory menaquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, three aminolipids, and two unidentified glycolipids. The cell-wall peptidoglycan contained meso-diaminopimelic acid as a diagnostic diamino acid. The genome comprised 2,663,796 bp, with a G + C content of 70.9%. Stress-responsive periplasmic chaperone/protease coding genes were identified in the genome of EF45031 and were not detected in other Brachybacterium species. The polyphasic taxonomic properties indicate that the strain represents a novel species within the genus Brachybacterium, for which the name Brachybacterium sillae sp. nov. is proposed. The type strain is EF45031 (= KCTC 49702 = NBRC 115869).