Hyphobacterium marinum sp. nov. and Hyphobacterium lacteum sp. nov., isolated from marine sediment

Two bacterial strains, Y60-23^T and HN-65^T, were isolated from marine sediment samples collected from Xiaoshi Island, Weihai, and Dongzhai Harbour, Haikou, PR China, respectively. Based on the 16S rRNA gene sequences, strain Y60-23^T exhibited 96.0% similarity to its most related type strain <i>Hyphobacterium vulgare</i> KCTC 52487^T, while strain HN-65^T exhibited 97.3% similarity to its most related type strain <i>Hyphobacterium indicum</i> 2ED5^T. The 16S rRNA gene sequence similarity between the two strains was 95.8%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains Y60-23^T and HN-65^T belonged to the genus <i>Hyphobacterium</i>. Cells of strains Y60-23^T and HN-65^T were rod-shaped, Gram-stain-negative, aerobic, non-motile, prosthecate and multiplied by binary fission. The major cellular fatty acids (>10.0%) of strain Y60-23^T were C_{18 : 1} <i> ω</i>7<i>c</i> and C_{17 : 0}, while those of strain HN-65^T were iso-C_{17 : 1} <i> ω</i>9<i>c</i>, iso-C_{17 : 0} and C_{18 : 1} <i> ω</i>7<i>c</i>. The major respiratory quinone in both strains was ubiquinone-10 (Q-10) and the major polar lipids were monoglycosyl diglyceride, sulfoquinovosyl diacylglycerol and glucuronopyranosyl diglyceride. The genomic DNA G+C contents of strains Y60-23^T and HN-65^T were 63.9 and 60.7 mol%, respectively. The average nucleotide identity value between the two strains was 72.1% and the DNA-DNA hybridization value was 18.4%, clearly distinguishing them from each other. According to the results of the phenotypic, chemotaxonomic, phylogenetic and genomic analyses, the two strains represented two novel species within the genus <i>Hyphobacterium</i>, for which the names <i>Hyphobacterium marinum</i> sp. nov. and <i>Hyphobacterium lacteum</i> sp. nov. were proposed with the type strains Y60-23^T (=MCCC 1H01433^T=KCTC 8172^T) and HN-65^T (=MCCC 1H01434^T=KCTC 8169^T), respectively.