Taxonomy and ecology of methanogens

More fhan nine reviews on taxonomy of methanogens have been published during the last decade [l-91, after the discovery of the unique biochemical and genetic properties of these organisms led to the concept of Archaebacteria at the end of the seventies. Moreover, important economic factors have ,placed these bacteria in the limelight [ 5 ] , including the need to develop alternative forms of energy, xenobiotic pollution control, the enhancement of meat yields in the cattle industry, the distinction between biological and thermocatalytic petroleum generation, and the global distribution of methane in the earth's atmosphere.