Roseibacula alcaliphilum gen. nov. sp. nov., a New Alkaliphilic Aerobic Anoxygenic Phototrophic Bacterium from a Meromictic Soda Lake Doroninskoe (East Siberia, Russia)

摘要

A bacterial strain De was isolated from the surface water layer of the meromictic soda lake Doroninskoe. When grown in the dark, it formed pink colonies on agar media. The cells were nonmotile, containing bacteriochlorophyll a and carotenoids. Stationary-phase cells contained intracellular vesicular membranes similar to the membranes of the photosynthetic apparatus of some nonsulfur purple bacteria. Aerobic growth did not occur. Sucrose, citrate, mannitol, sorbitol, casein hydrolysate, and yeast extract were the preferable substrates for aerobic growth. Xylose, lactose, aspartate, benzoate, malate, malonate, succinate, tartrate, formate, fumarate, glycerol, methanol, and ethanol were not utilized. Growth occurred at up to 50 g/L NaCl (optimum at 5 g/L) and pH 9.8. According to the 16S rRNA gene sequencing, similarity between the isolate and the known alkaliphilic genera of nonsulfur purple bacteria (Rhodobaca) and of aerobic anoxygenic phototrophic bacteria (Roseinatronobacter) was 96%, which was sufficient for the description of a new genus of aerobic anoxygenic phototrophic bacteria. The name Roseibacula alcaliphilum gen. nov., sp. nov. was proposed for the isolate.