Actibacterium pelagium sp. nov., a novel alphaproteobacterium, and emended description of the genus Actibacterium

A Gram-stain-negative, non-motile, rod-shaped bacterium, designated JN33^T, was isolated from seawater collected from the western Pacific Ocean. Strain JN33^T was positive for hydrolysis of aesculin and gelatin. On the basis of 16S rRNA gene sequence analysis, strain JN33^T showed high 16S rRNA gene sequence similarity to Actibacterium atlanticum 22II-S11-z10^T (97.3 %), A. mucosum KCTC 23349^T (96.6 %) and A. ureilyticum LS-811^T (95.7 %) and exhibited less than 97.0 % 16S rRNA gene sequence similarity with respect to the other type strains within the family Rhodobacteraceae. Phylogenetic analysis revealed that strain JN33^T fell within the cluster of the genus Actibacterium. The average nucleotide identity and in silico DNA-DNA hybridization values between strain JN33^T and the type strains of Actibacterium species were 73.1-73.8 % and 19.8-20.1 %, respectively. The sole respiratory quinone was ubiquinone 10 (Q-10). The principal fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The major polar lipids were phosphatidylglycerol, one unidentified phospholipid and two unidentified aminolipids. The DNA G+C content was 57.8 mol%. Distinctly different phylogenetic characteristics, chemotaxonomic differences, as well as phenotypic properties, revealed that strain JN33^T could be differentiated from the Actibacterium species with validly published names. Therefore, it is proposed that strain JN33^T represents a novel species of the genus Actibacterium, for which the name Actibacterium pelagium sp. nov. (type strain, JN33^T=CGMCC 1.16012^T=KCTC 52653^T) is proposed.