PSYCHROPHILIC METHANOTROPH FROM TUNDRA SOIL

The first psychrophilic obligate methanotroph was isolated from the tu ndra soil in the Polar Ural. The organism has an optimal temperature r ange of 3.5-degrees-10-degrees-C, but at 20-degrees-C the growth is mi nimal. The cells of the metanotroph are Gram-negative cocci resembling Methylococcus in appearance but of low G + C content (G + C = 45.6 mo l%). Membranes are arranged into bundles of vesicular discs. Gas vesic les are formed at the temperature range of 7-degrees-20-degrees-C, and the number of cells with vesicles increases with the temperature. Onl y methane or methanol serves as substrate for growth in the mineral sa lt medium. Psychrophilic methanotrophs might be important components o f a microbial gas filter in the tundra region.