Abstract
Methanospirillum hungatei strain JF1 (DSM 864) is a methane-producing archaeon and is the type species of the
genus Methanospirillum, which belongs to the family Methanospirillaceae within the order Methanomicrobiales. Its
genome was selected for sequencing due to its ability to utilize hydrogen and carbon dioxide and/or formate as a
sole source of energy. Ecologically, M. hungatei functions as the hydrogen- and/or formate-using partner with many
species of syntrophic bacteria. Its morphology is distinct from other methanogens with the ability to form long
chains of cells (up to 100 μm in length), which are enclosed within a sheath-like structure, and terminal cells with
polar flagella. The genome of M. hungatei strain JF1 is the first completely sequenced genome of the family
Methanospirillaceae, and it has a circular genome of 3,544,738 bp containing 3,239 protein coding and 68 RNA
genes. The large genome of M. hungatei JF1 suggests the presence of unrecognized biochemical/physiological
properties that likely extend to the other Methanospirillaceae and include the ability to form the unusual sheath-like
structure and to successfully interact with syntrophic bacteria.