Methanogenium frigidum SMCC 459W Dataset NCBI Taxonomy Classification phylum Euryarchaeota class Methanomicrobia order Methanomicrobiales family Methanomicrobiaceae genus Methanogenium species Methanogenium frigidum Name Homonyms Methanogenium frigidum Methanogenium frigidum SMCC 459W Methanogenium frigidum Franzmann et al. 1997