Marinicellulosiphila megalodicopiae gen. nov., sp. nov., a deep-sea alkaliphilic cellulolytic bacterium isolated from an endemic ascidian Megalodicopia hians

The strain TOYAMA8^T is a deep-sea alkaliphilic cellulolytic bacterium isolated from a slurry-adhered epiphytic site of <i>Megalodicopia hians</i>. Cells of this strain are Gram-negative, aerobic, curved rods or spirilla, motile with monopolar flagella, and grow on cellulose as the sole carbon source. Compared to other closely related species, this bacterium is characterized by a large number of cellulase genes. Strain TOYAMA8^T showed alkaliphilic growth within the pH range 7.5-9.0. The major cellular fatty acids were C_{18 : 1} ω7, C_{14 : 0}, C_{16 : 0} and C_{16 : 1} ω7. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipids and aminolipids. A major respiratory lipoquinone was Q-9. Phylogenomic analysis using the 16S rRNA gene and whole-genome sequence data showed that the strain is related to the families <i>Gynuellaceae</i>, <i>Saccharospirillaceae</i> and <i>Natronospirillaceae</i>. The values of 16S rRNA gene sequence similarity, amino acid identity and percentage of conserved proteins between the strain TOYAMA8^T and related species were low, with maximum values of 90.6, 48.1 and 34.6%, respectively. These results, together with differences in phenotypic and biochemical characteristics, indicate that the new isolate TOYAMA8^T represents a novel genus and species, for which the name <i>Marinicellulosiphila megalodicopiae</i> gen. nov., sp. nov., is proposed. The type strain is TOYAMA8^T (JCM 31119^T=DSM 114864^T).