Ectothiorhodospira variabilis sp. nov., an alkaliphilic and halophilic purple sulfur bacterium from soda lakes.

During studies of moderately halophilic strains of Ectothiorhodospira from steppe soda lakes, we found a novel group of bacteria related to Ectothiorhodospira haloalkaliphila with salt optima at 50-80 g NaCl l(-1). Phylogenetic analysis using 16S rRNA gene sequences of strains from soda lakes in Mongolia, Egypt and Siberia revealed separation of the group of new isolates from other Ectothiorhodospira species, including the closely related Ect. haloalkaliphila.