Saccharophagus degradans gen. nov., sp. nov., a versatile marine degrader of complex polysaccharides

Gammaproteobacteria belonging and related to the genus Microbulbifer are an emerging group of complex carbohydrate-degrading marine bacteria. Previously, all of the representatives were placed within Microbulbifer or were unclassified. Recently, a new genus, Teredinibacter, represented by a single species, Teredinibacter turnerae, was formed to include an endosymbiotic branch of these organisms. In this study, based on 16S rRNA gene sequence similarity and phenotypic analyses, a new genus, Saccharophagus, is proposed to accommodate the most versatile marine carbohydrate degrader yet identified, Saccharophagus degradans gen. nov., sp. nov. 2-40(T) (=ATCC 43961(T)=DSM 17024(T)). S. degradans strain 2-40(T) can degrade 10 tested complex polysaccharides: agar, alginate, chitin, cellulose, fucoidan, laminarin, pectin, pullulan, starch and xylan. S. degradans 2-40(T) shares 90.5% 16S rRNA gene sequence similarity with the type strain of the Microbulbifer type species, Microbulbifer hydrolyticus IRE-31(T), and 91.5% with T. turnerae T7902(T), and can be further distinguished from members of these two genera by 16S rRNA gene cluster analysis, the ability to utilize 10 different complex polysaccharides as sole carbon sources, a significantly lower G+C content and differences in fatty acid content. The three genera of complex polysaccharide-degrading, marine bacteria now encompass 20 strains from diverse marine niches.