Stackebrandtia cavernae sp. nov., a novel actinobacterium isolated from a karst cave sample.

A novel actinobacterial strain, YIM ART06T, was isolated from a rock sample of karst cave located at Guizhou province, south-west China, and was characterized by a polyphasic taxonomic approach. The morphological and chemotaxonomic properties of strain YIM ART06T were in accordance with those of the genus Stackebrandtia. The 16S rRNA gene sequence of strain YIM ART06T showed highest similarity to Stackebrandtia nassauensis JCM 14905T (98.0 %). The DNA-DNA hybridization value between strains YIM ART06T and S. nassauensis JCM 14905T was, however, moderately high (62.9 %) but below the 70 % limit for species identification. Strain YIM ART06T contained meso-diaminopimelic acid as the diagnostic diamino acid, and mannose, ribose and xylose in the whole-cell hydrolysates. The predominant menaquinones detected were MK-10(H4), MK-10(H6), MK-11(H4) and MK-11(H6), while the cell membrane polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmethylethanolamine and three unidentified phospholipids. The genomic DNA G+C content of strain YIM ART06T was 71 mol%. The major fatty acids were anteiso-C17 : 0, iso-C17 : 0, iso-C16 : 0 and iso-C15 : 0. Based on the taxonomic characteristics from the genotypic and phenotypic results, strain YIM ART06T merits recognition as a representative of a novel species of the genus Stackebrandtia, for which the name Stackebrandtia cavernae sp. nov. is proposed. The type strain is YIM ART06T ( = KCTC 39599T = CCTCC AA 2015021T = DSM 100594T).