Microbacterium wangchenii sp. nov., isolated from faeces of Tibetan gazelles (Procapra picticaudata) on the Qinghai-Tibet Plateau

Abstract

Two strains of Gram-stain-positive, aerobic, non-spore-forming, non-motile, rod-shaped bacteria (designated dk512^T and dk508) were isolated from the faeces of Tibetan gazelle (<i>Procapra picticaudata</i>) collected from the Qinghai-Tibet Plateau, PR China. The 16S rRNA gene sequences of the strains showed the highest identity to <i>Microbacterium saccharophilum</i> K-1^T (98.0 and 97.9 % similarity, respectively). The phylogenetic analysis based on 16S rRNA gene sequences revealed that dk512^T and dk508 were members of the genus <i>Microbacterium</i>, and most closely related to strains <i>Microbacterium mitrae</i> M4-8^T and <i>Microbacterium hatanonis</i> FCC-01^T. The strains grew optimally on brain-heart infusion (BHI) agar with 5.0 % (v/v) sheep blood at 30 °C, pH 7.0 and with 1.0 % (w/v) NaCl. The genome of type strain dk512^T was 3.8 Mb with a G+C content of 70.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain dk512^T and previously characterized <i>Microbacterium</i> species were <95 and <70 %, respectively. In strain dk512^T, the detected primary cellular fatty acids were anteiso-C_{15 : 0} and anteiso-C_{17 : 0}, the main respiratory quinones were MK-9 (37.9 %) and MK-10 (35.7 %), and the polar lipids included diphosphatidylglycerol, phosphatidylglycerol and three unidentified glycolipids. The major cell-wall sugars were rhamnose, ribose and galactose. Alanine, glutamic acid, glycine and ornithine were in the cell-wall peptidoglycan. Based on phenotypic data and phylogenetic inference, these two strains represent a novel species of the genus <i>Microbacterium</i>, named here as <i>Microbacterium wangchenii</i> sp. nov, where dk512^T is designated the type strain (=CGMCC 1.16590^T=JCM 33494^T=KCTC 49313^T).