Marinobacterium nitratireducens sp. nov. and Marinobacterium sediminicola sp. nov., isolated from marine sediment

Two strains, CN44(T) and CN47(T), isolated from marine sediment of the East China Sea, were characterized by using a polyphasic approach. The isolates were Gram-negative, strictly aerobic, non-spore-forming rods. The chemotaxonomic characteristics of these isolates included the presence of C(18 : 1)omega7c, C(16 : 0), iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c and C(10 : 0) 3-OH as the major cellular fatty acids and Q-8 as the predominant ubiquinone. The DNA G+C contents of strains CN44(T) and CN47(T) were 62.5 and 56.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain CN44(T) was related to members of the genus Marinobacterium. The most closely related described organism was the type strain of Marinobacterium rhizophilum (95.3 % sequence similarity). Strain CN47(T) showed the highest sequence similarity to the type strain of Marinobacterium stanieri (97.8 %) and <97 % similarity to other type strains of described Marinobacterium species. The level of DNA-DNA relatedness between strain CN47(T) and M. stanieri DSM 7027(T) was 46 %. On the basis of phenotypic and genotypic properties, strains CN44(T) and CN47(T) represent two novel species within the genus Marinobacterium, for which the names Marinobacterium nitratireducens sp. nov. (type strain, CN44(T) =CGMCC 1.7286(T) =JCM 15523(T)) and Marinobacterium sediminicola sp. nov. (type strain, CN47(T) =CGMCC 1.7287(T) =JCM 15524(T)) are proposed.