[Features of nine strains of thermophilic methanogens]

Nine strains of thermophilic bacteria producing methane from hydrogen and carbon dioxide or formate were isolated and purified from four samples of anaerobic digester feeding with family waste water. They are similar with each other on cell morphology and physiological characteristics. The cells are straight or slightly curved with rounded ends, 0.3-0.4 x 1-3 microns; single or in pairs, sometimes joined into long chains (> 10 microns); Gram-positive, non-mo-tile, non-spore-forming. The organisms under fluorescence microscope shine green fluorescence specific for methanogens and are chemoautotrophs. The temperature range for growth is 30-75 degrees C, optimum 55-65 degrees C. The initial pH range for growth is 5.8-9.0, optimum 6.9-7.6. The G + C content of DNA of the strain 602B3 is 44.6 mol%. According to the results of identification, the strain 602B3 is considered of belonging to species Methanobacterium thermoformicicum 602B3.