Draconibacterium mangrovi sp. nov., isolated from mangrove sediment

A marine bacterial strain, designated GM2-18 T , was isolated from mangrove sediment sampled at Luoyang River estuary, Quanzhou, PR China. Cells were Gram-stain-negative, slightly curved long rod-shaped and facultatively anaerobic with no flagellum. Catalase activity was found to be weak-positive and oxidase-positive. It had no ability to degrade or hydrolyse substrates including skimmed milk, cellulose, starch and Tweens (40, 60 and 80). The 16S rRNA gene sequence of strain GM2-18 T had maximum similarity values to ‘ Draconibacterium filum ’ F2 T , Draconibacterium sediminis JN14CK-3 T and Draconibacterium orientale FH5 T of 98.0, 97.8 and 97.4 %, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GM2-18 T was affiliated to the genus Draconibacterium and formed a clade with an uncultured bacterium clone identified from mangrove environment. Average nucleotide identity values and DNA–DNA hybridization estimates of strain GM2-18 T compared to its Draconibacterium relatives strongly supported that it belonged to a new species. The respiratory quinone was menaquinone MK-7. The major fatty acids (>10 %) consisted of iso-C 15 : 0 , anteiso-C 15 : 0 and C 17 : 1  ω 6 c . The polar lipids were phosphatidylethanolamine, a phospholipid and several unidentified lipids. The genomic size of strain GM2-18 T was 5.9 Mb and the G+C content was 40.8 mol%. Gene prediction and annotation of strain GM2-18 T indicated that there was a nitrogen-fixing gene cluster encoding nitrogenase molybdenum-iron protein and related proteins responsible for nitrogen fixation. Based on the above characteristics, strain GM2-18 T represents a novel species within the genus Draconibacterium . Thus, Draconibacterium mangrovi sp. nov. is proposed with type strain GM2-18 T (=MCCC 1K04382 T =KCTC 72879 T ), isolated from mangrove sediment.