Methanogene Bakterien

Methanogenic bacteria area diverse group of anaerobic procaryotes that ferment CO₂ plus H₂ to CH₄. Besides their unusual energy metabolism they are unique in that their cell walls do not contain murein, and in that their cell membranes are composed of isoprenoid lipids. Coenzymes occur which are not found in any other living organism. The translation apparatus differs, e.g., in not being affected by antibiotics known to be inhibitors of procaryotic protein synthesis. Most of the methanogens can grow on CO₂ as sole carbon source; autotrophic CO₂ fixation does not, however, proceed via reactions of the Calvin cycle. Molecular genealogical analysis has revealed that methanogenic bacteria constitute a grouping phylogenetically distinct from most other procaryotes.