[New brown chlorobacteria Prosthecochloris phaeoasteroidea nov. sp].

Two strains of new photosynthetic bacteria were isolated from salt meromictic lakes Mogilnoye and Faro. The bacteria are abligate phototrophic anaerobic cultures which utilize H2S as an electron donor by oxidizing it to elementary sulphur and sulphates. Sulphur is liberated outside the cell. The cultures contain bacteriochlorophyll e and carotenoids of the isorenierathene type. Photosynthetic structures are represented by chlorobium-vesicles. According to these properties, the cultures belong to the Chlorobiaceae family. The bacteria have no gas vacuoles. The cells form 10--20 apophyses-prosthecae which is typical of the Prostheocochloris genus. The new strains differ from Prosthecochloris aestuarii by the brown colour of the cell suspension, the composition of pigments, and ecology. They are classed as a new species Prostheocochloris phaeoasteroidea nov. sp. Diagnosis of the new species is presented.