Hydrogenotrophic methanogens

The findings clearly indicate that the last step of the CO2 reduction pathway, the reduction of CoM-S-S-HTP by H2, is a coupling site for ATP synthesis. It is concluded that CoM-S-S-HTP is the terminal electron acceptor ( = —200 mV) of a membrane-bound electron transport chain, with molecular H2 ( ° = -414mV) being the electron donor in hydrogenotrophic methanogens [115]. The physiological electron donor for CoM-S-S-HTP reduction is not known (Fig. 5). 

In a survey of five methanogenic species drawn from a wide range of phylogenetic and physiological types, all the hydrogenotrophs... 

Castro, H., S. Newman, K. R. Reddy, and A. Ogram. 2005. Distribution and stability of sulfate-reducing prokaryotic and hydrogenotrophic methanogenic assemblages in nutrient-impacted regions of the Florida Everglades. Environ. Microbiol. 71 2695-2704. 

Methanogenes use as donor of electrons for the reduction of carbon. A leading role in this case is played by hydrogenotrophic methanogenes ... 

Depending on the electron donor the methanogens at this stage, as mentioned before, are subdivided into two groups acetoclastic and hydrogenotrophic. 

Hydrogen losses mainly occur via diffusion of gas through the membrane into the anode chamber, where it can be consumed by hydrogenotrophic methanogens to make methane [15, 16]. This can be especially problematic in... 

This is a greater energy yield than derived from acetate (-31 kJ mol methane, Table 1.2), and hydrogenotrophic methanogens grow much more quickly that acetate-utilizing methanogens. 

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