Microbacterium profundi sp. nov., isolated from deep-sea sediment of polymetallic nodule environments.

A Gram-positive, aerobic, neutrophilic and rod-shaped bacterium, strain Shh49(T), was isolated from a deep-sea sediment sample collected from the East Pacific polymetallic nodule region. The strain was able to grow within a temperature range of 4-35 degrees C and tolerated up to 7.5 % (w/v) NaCl. Strain Shh49(T) was characterized chemotaxonomically by having MK-12 and MK-13 as predominant isoprenoid quinones, anteiso-C(15 : 0), iso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0) as major fatty acids and ornithine as cell-wall diamino acid. The genomic DNA G+C content was 66.8 mol%. On the basis of 16S rRNA gene sequence similarities, the closest phylogenetic neighbours were the type strains of Microbacterium phyllosphaerae (98.3 %) and Microbacterium keratanolyticum (98.0 %), but strain Shh49(T) could be clearly distinguished from its phylogenetic relatives with reference to a broad range of physiological and biochemical markers. DNA-DNA relatedness of strain Shh49(T) with M. phyllosphaerae DSM 13468(T) and M. keratanolyticum DSM 8606(T) was 56 and 31 %, respectively. On the basis of phenotypic and genotypic data presented in this study, strain Shh49(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium profundi sp. nov. is proposed. The type strain is Shh49(T) (=CGMCC 1.6777(T) =JCM 14840(T)).