Iodidimonas muriae gen. nov., sp nov., an aerobic iodide-oxidizing bacterium isolated from brine of a natural gas and iodine recovery facility, and proposals of Iodidimonadaceae fam. nov., Iodidimonadales ord. nov., Emcibacteraceae fam. nov and Emcibacterales ord. nov.

A chemo-organotrophic iodide (1(-))-oxidizing bacterial strain, C-3(T), isolated from natural gas brine of an iodine recovery facility in Kujukuri, Chiba, Japan, was characterized for representation of a novel species in the class Alphaproteobacteria. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the nearest neighbours of strain C-3(T) were members of the genera Eilatimonas, Kordiimonas, Rhodothalassium and Temperatibacter with 88-91% sequence similarity. Cells of strain C-3(T) were aerobic, Gram-staining-negative, non-sporulating and rod shaped (1.3-3.6 mu m in length). Strain C-3(T) grew optimally at 30 degrees C, pH 7.5 and with 3% NaCl (w/v). Iodide oxidation to form molecular iodine (12) was a unique trait for strain C-3(T), whereas the strain did not utilize iodide as a sole electron donor for chemolithoautotrophic growth. The major isoprenoid quinone was Q-10. The major cellular fatty acids were C-18:1 omega 7c and C-16:1 omega 5c. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified aminolipids. The G+C content of the genomic DNA was 58.5 mol%. Iodide oxidation and the major cellular fatty acids composition distinguished strain C-3(T) from phylogenetically related bacteria. On the basis of the phenotypic features and the phylogenetic position, a novel genus and species are proposed for strain C-3(T) (=JCM 17843(T)=LMG 28660(T)), to be named lodidimonas muriae gen. nov., sp. nov. We also propose to place the distinct sublineages of the genera lodidimonas gen. nov. and Emcibacter in the orders lodidimonadales ord. nov. and Emcibacterales ord. nov., respectively, because these genera are located far apart from the order Kordiimonadales and form the distinct lineage in the class Alphaproteobacteria.