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

Abstract

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 Hyphobacterium vulgare KCTC 52487^T, while strain HN-65^T exhibited 97.3% similarity to its most related type strain Hyphobacterium indicum 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 Hyphobacterium. 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  ω7c and C_17 : 0, while those of strain HN-65^T were iso-C_17 : 1  ω9c, iso-C_17 : 0 and C_18 : 1  ω7c. 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 Hyphobacterium, for which the names Hyphobacterium marinum sp. nov. and Hyphobacterium lacteum 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.