Thalassobius mediterraneus gen. nov., sp. nov., and reclassification of Ruegeria gelatinovorans as Thalassobius gelatinovorus comb. nov.

A Gram-negative, slightly halophilic, non-pigmented, strictly aerobic, chemo-organotrophic bacterium was isolated from sea water off the western Mediterranean coast near Valencia (Spain). This strain was able to grow on several organic acids and amino acids added to a minimal medium as carbon sources, but used few carbohydrates or yielded slight growth when sugars were used. Phylogenetic analysis based on an almost complete 16S rRNA gene sequence revealed that strain XSM19T was a member of the Roseobacter group within the 'Alphaproteobacteria', with its closest phylogenetic neighbour being Ruegeria gelatinovorans (97.6 % sequence similarity). Following a polyphasic approach, it was concluded that strain XSM19T represents a new genus and novel species, for which the name Thalassobius mediterraneus sp. nov. is proposed. The type strain is XSM19T (=CECT 5383T=CIP 108400T=CCUG 49438T). It is also proposed that R. gelatinovorans (Rüger & Höfle 1992) Uchino et al. 1999 is reclassified as Thalassobius gelatinovorus comb. nov.