Which genes are crucial for the energy metabolism of Archaea?

Microorganisms are still often perceived only as disease promoters, although the vast majority of them plays an important ecological role in the global geochemical cycles: without the metabolic activities of the smallest of all living organisms, bacteria and archaea, life on Earth would not be possible. It is now also known from microbiome research that our gut bacteria affect not only our general health, but even our psyche, report investigators.