Teredinibacter haidensis sp. nov., Teredinibacter purpureus sp. nov. and Teredinibacter franksiae sp. nov., marine, cellulolytic endosymbiotic bacteria isolated from the gills of the wood-boring mollusc Bankia setacea (Bivalvia: Teredinidae) and emended description of the genus Teredinibacter

Here, we describe three endosymbiotic bacterial strains isolated from the gills of the shipworm, Bankia setacea (Teredinidae: Bivalvia). These strains, designated as Bs08(T), Bs12(T) and Bsc2(T), are Gram- stain-negative, microaerobic, gammaproteobacteria that grow on cellulose and a variety of substrates derived from lignocellulose. Phenotypic characterization, phylogeny based on 16S rRNA gene and whole genome sequence data, amino acid identity and percentage of conserved proteins analyses, show that these strains are novel and may be assigned to the genus Teredinibacter. The three strains may be differentiated and distinguished from other previously described Teredinibacter species based on a combination of four characteristics: colony colour (Bs12(T), purple; others beige to brown), marine salt requirement (Bs12(T), Bsc2(T) and Teredinibacter turnerae strains), the capacity for nitrogen fixation (Bs08(T) and T. turnerae strains) and the ability to respire nitrate (Bs08(T)). Based on these findings, we propose the names Teredinibacter haidensis sp. nov. (type strain Bs08(T)=ATCC TSD-121(T)=KCTC 62964(T)), Teredinibacter purpureus sp. nov. (type strain Bs12(T)=ATCC TSD-122(T)=KCTC 62965(T)) and Teredinibacter franksiae sp. nov. (type strain Bsc2(T)=ATCC TSD-123(T)=KCTC 62966(T)).

Automated summary

In this study, three novel endosymbiotic bacterial strains isolated from the shipworm were characterized and proposed as new species within the genus Teredinibacter based on phenotypic and genotypic analyses. These strains exhibit unique characteristics such as marine salt requirement, nitrogen fixation capacity, and respiratory nitrate ability, distinguishing them from previously described Teredinibacter species.