gen. nov. sp. nov., a member of the family with alginate-degradation activity, isolated from marine alga .

A Gram-stain-negative, aerobic, yellow, non-motile, rod-shaped and alginate-degrading bacterium, designated Dm15, was isolated from marine alga collected in Weihai, PR China. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Dm15 represents a distinct line of the family . Strain Dm15 had the highest 16S rRNA gene sequence similarity to its closest phylogenetic neighbour (96.7 %) and 93.7-96.4 % sequence similarity to other phylogenetic neighbours (, , , and ) in the family . The novel isolate was able to grow at 10-40 °C (optimum, 30-33 °C), pH 7.0-9.0 (optimum, pH 7.0-7.5) and with 0.5-6.0 % NaCl (optimum 2.0-3.0 %, w/v). It could grow at 40 °C, and degrade alginate and cellulose, which were different from the neighbour genera. The draft genome consisted of 3395 genes with a total length of 3 798 431 bp and 34.1mol% G+C content. Especially, there were some specific genes coding for cellulase and alginate lyase, which provided a basis for the above phenotypic characteristics. The strain's genome sequence showed 71.1-80.2 % average amino acid identity values and 71.8-77.7 % average nucleotide identity values compared to the type strains of related genera within the family . It shared digital DNA-DNA hybridization identity of 19.8 and 20.9 % with and , respectively. The sole menaquinone was MK-6. The major fatty acids were iso-C and iso-C G. The polar lipids included six unidentified polar lipids, four unidentified aminolipids and phosphatidylethanolamine. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain Dm15 represents a novel species of a new genus in the family , phylum , for which the name gen. nov., sp. nov. is proposed. The type strain is Dm15 (KCTC 42256=CICC 23815).