shift from acetoclastic to H2-dependent methanogenesis in a west Siberian peat bog at low pH values and isolation of an acidophilic Methanobacterium strain.

Methane production and archaeal community composition were studied in samples from an acidic peat bog incubated at different temperatures and pH values. H(2)-dependent methanogenesis increased strongly at the lowest pH, 3.8, and Methanobacteriaceae became important except for Methanomicrobiaceae and Methanosarcinaceae. An acidophilic and psychrotolerant Methanobacterium sp. was isolated using H(2)-plus-CO(2)-supplemented medium at pH 4.5.