ABSTRACT
Nonphotosynthetic pathways for carbon dioxide fixation are those performed by the bacterial methanogens, which are a subgroup within the kingdom of the archaea. Archaea, together with bacteria and eucarya, form the three domains of life. In anaerobic microorganisms, the Calvin cycle for CO2 fixation does not operate, and acetyl-coenzyme A (CoA) is the central intermediate in carbon metabolism. l -4 Considerable efforts have been made during the last decade to mimic the natural process of photosynthesis, using reaction systems which included photosensitizers, electron transfer mediators, and sometimes sacrificial electron donors.
