Straight or slightly curved rods (0.3-0.4 x 1-3 microns), singly or in pairs but never long filaments.Non-mobile and Gram-positive. Extreme thermophilic with an optimum temperature of 83 ° C and a maximum temperature of 97 ° C. CH4 is produced from H2 + CO2 exclusively. Requires yeast extract for growth. No growth on agar, colonies are obtained polysilicate. The cell wall contains a pseudomurein lined with a layer of protein. DNA contains 33 mol% G+ C. Two species isolated from hot springs, which Methanothermus fervidus .
