Microbacterium arthrosphaerae sp. nov., isolated from the faeces of the pill millipede Arthrosphaera magna Attems.

A Gram-reaction-positive, rod-shaped bacterium, designated strain CC-VM-Y(T), was isolated from the faeces of the pill millipede Arthrosphaera magna Attems from India and was subsequently studied to determine its taxonomic position. Based on16S rRNA gene sequence similarities, the isolate clearly grouped with members of the genus Microbacterium. On the basis of pairwise comparisons of the 16S rRNA gene sequences, strain CC-VM-Y(T) was most closely related to Microbacterium insulae DS-66(T) (98 %), Microbacterium hydrocarbonoxydans DSM 160809(T) (97.8 %) and Microbacterium hominis NBRC 15708(T) (97.9 %). The peptidoglycan contained the amino acids ornithine (Orn), alanine (Ala), glycine (Gly), homoserine (Hsr) and glutamic acid (Glu) in an approximate molar ratio of 1.0 : 0.8 : 2.2 : 0.8 : 0.3. In addition, substantial amounts of threo-3-hydroxy glutamic acid (Hyg) were detected, which is characteristic of peptidoglycan type B2β. The acyl type of the peptidoglycan was glycolyl. The menaquinones of strain CC-VM-Y(T) were MK-13 (72 %), MK-12 (25 %) and MK-11 (3 %). The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, one unknown phospholipid and one unknown glycolipid. The fatty acid profile comprised anteiso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0) as the major fatty acids, which was congruent with fatty acid profiles of other members of the genus Microbacterium. The results of physiological and biochemical tests as well as DNA-DNA hybridizations with the most closely related species, M. insulae, M. hydrocarbonoxydans and M. hominis, revealed clear phenotypic and genotypic differences between strain CC-VM-Y(T) and other members of the genus Microbacterium. Based on these results, strain CC-VM-Y(T) ( = DSM 22421(T)  = CCM 7681(T)) represents a new species of the genus Microbacterium, for which the name Microbacterium arthrosphaerae sp. nov. is proposed.