Microbacterium phosphatis sp. nov., an actinomycete isolated from a phosphate mine

Two Gram-staining-positive, non-motile and non-spore-forming bacterial strains, designated as 9H2 T and YDN13, were isolated from a phosphate mine in Yunnan Province, China. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains 9H2 T and YDN13 belong to the genus Microbacterium . Results show that strains 9H2 T and YDN13 occupied a distinct position within the genus Microbacterium and showed the highest 16S rRNA gene sequence similarity of 97.6% with the type strains of Microbacterium thalassium CCTCC AB 2020140 T , followed by 97.5% with Microbacterium hydrocarboxydans DSM 16089 T and 97.3% with Microbacterium stercoris CCTCC AA 2018028 T . In the phylogenetic trees based on 16S rRNA gene sequences, strains 9H2 T and YDN13 were closely related to M. stercoris CCTCC AA 2018028 T and Microbacterium sediminicola YM 10-847 T . Strains 9H2 T and YDN13 showed the highest values of an orthologous average nucleotide identity (84%) and a digital DNA–DNA hybridization (49%) with M. stercoris CCTCC AA 2018028 T , followed by an orthologous average nucleotide identity of 76.0% and a digital DNA–DNA hybridization value of 17.9% with M. thalassium CCTCC AB 2020140 T . The respiratory menaquinones were MK-11, MK-12, MK-10 and MK-13. The major fatty acid profile contained anteiso-C 15 : 0 , iso-C 16 : 0 and anteiso-C 17 : 0 . The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and one unidentified glycolipid. The whole-cell sugars included galactose and glucose. The peptidoglycan hydrolysate contained glutamate, glycine, ornithine and alanine. The DNA G+C contents were 71.1 mol%. Phenotypic, phylogenetic, chemotaxonomic and genomic analyses revealed that strains 9H2 T and YDN13 represent a novel species of Microbacterium , for which the name Microbacterium phosphatis sp. nov. was proposed. The type strain is 9H2 T (MCCC 1K08680 T =KCTC 59053 T =CGMCC 1.60061 T ).