sp. nov., a marine, cellulolytic endosymbiotic bacterium isolated from the gills of the wood-boring mollusc (Bivalvia: Teredinidae) and emended description of the genus .

A cellulolytic, aerobic, gammaproteobacterium, designated strain Bs02, was isolated from the gills of a marine wood-boring mollusc, (Bivalvia: Teredinidae). The cells are Gram-stain-negative, slightly curved motile rods (2-5×0.4-0.6 µm) that bear a single polar flagellum and are capable of heterotrophic growth in a simple mineral medium supplemented with cellulose as a sole source of carbon and energy. Cellulose, carboxymethylcellulose, xylan, cellobiose and a variety of sugars also support growth. Strain Bs02 requires combined nitrogen for growth. Temperature, pH and salinity optima (range) for growth were 20 °C (range, 10-30 °C), 8.0 (pH 6.5-8.5) and 0.5 M NaCl (range, 0.0-0.8 M), respectively when grown on 0.5 % (w/v) galactose. Strain Bs02 does not require magnesium and calcium ion concentrations reflecting the proportions found in seawater. The genome size is approximately 4.03 Mbp and the DNA G+C content of the genome is 47.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences, and on conserved protein-coding sequences, show that strain Bs02 forms a well-supported clade with . Average nucleotide identity and percentage of conserved proteins differentiate strain Bs02 from at threshold values exceeding those proposed to distinguish bacterial species but not genera. These results indicate that strain Bs02 represents a novel species in the previously monotypic genus for which the name sp. nov. is proposed. The strain has been deposited under accession numbers ATCC TSD-120 and KCTC 62963.