sp. nov., a new actinobacterium isolated from a cave.

A novel Gram-stain-positive actinobacterial strain, designated C9-28, was isolated from soil sampled in a natural cave on Jeju Island, Republic of Korea. Strain C9-28 morphologically exhibited a rod-coccus life cycle and grew at 10-37 °C (optimum, 30 °C), pH 6-9 (optimum, pH 7) and 0-3 % (optimum, absence of NaCl). In the maximum-likelihood tree based on 16S rRNA gene sequences, strain C9-28 formed a sublineage between a clade and the type strain of . The closest relatives of strain C9-28 were the type strains of (98.88 % 16S rRNA gene sequence similarity), (98.88 %) and (98.60 %). The phylogenomic tree based on whole genome sequences supported the distinct position of the novel strain within the genus . The following chemotaxonomic characteristics also supported the assignment to the genus: -diaminopimelic acid; arabinose and galactose in whole-cell hydrolysates; the predominant menaquinone of MK-8(H); and polar lipids including diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, three unidentified glycolipids and two unidentified lipids. The predominant cellular fatty acids were C, summed feature 3 (Cω7 and/or Cω6), Cω9 and C. Based on the values of average nucleotide identity and digital DNA-DNA hybridization from whole genome sequences, and DNA-DNA hybridization between the isolate and the closest relatives, strain C9-28 (=KACC 19823=DSM 107559) represents a novel species of the genus , for which the name sp. nov. is proposed.