Rhodococcus antarcticus sp. nov., isolated from a till sample of Collins glacier front, Antarctica.

A pink-coloured, Gram-stain-positive, aerobic and rod-shaped strain, designated 75, was isolated from Collins glacier front till, Antarctica. Strain 75 was non-motile and non-spore-forming. Growth was observed at pH 6.0-9.0 (optimum, pH 7.0), at 4-45 °C (optimum, 20 °C) and with 0-9 % (w/v) NaCl (optimum, 1%). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 75 belongs to the genus , and is related to DSM 104003, KCTC29240 and KCTC 39118 (96.1, 96.0 and 95.7 % sequence similarity, respectively). The main polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and a phosphoglycolipid. The major cellular fatty acids were identified as C, iso- C, 10-methyl C and C 8. MK-7 and MK-8(H) were found to be the dominant menaquinones. Whole-cell hydrolysates contained -diaminopimelic acid, ribose, galactose, glucose and rhamnose. The genome of strain 75 is 3.82 Mb long in size with a G+C content of 73.1 mol%. On the basis of phenotypic, molecular and chemotaxonomic characteristics, strain 75 is considered to represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is 75 (=CCTCC AA 2019032=KCTC 49334).