Genomic Comparison, Phylogeny and Taxonomic Reevaluation of the and Description of fam. nov. and gen. nov.

The family represents purple sulfur bacteria of the found primarily in alkaline soda lakes of moderate to extremely high salinity. The main microscopically visible characteristic separating them from the is the excretion of the intermediate elemental sulfur formed during oxidation of sulfide prior to complete oxidation to sulfate rather than storing it in the periplasm. We present a comparative study of 38 genomes of all species of phototrophic . We also include a comparison with those chemotrophic bacteria that have been assigned to the family previously and critically reevaluate this assignment. The data demonstrate the separation of species in a major phylogenetic branch distant from other and support their separation into a new family, for which the name fam. nov. is proposed. In addition, the green-colored, bacteriochlorophyll-containing species and were transferred to the new genus gen. nov. of this family. The data also enable classification of several so far unclassified isolates and support the separation of and as well as and as distinct species.