Formate Formation and Formate Conversion in Biological Fuels Production

Figure 2

Carbon flux in methanogenic environments. Primary fermenting organisms (Group 1) degrade complex polymers to monomers, fatty acids, alcohols, hydrogen, carbon dioxide, acetate, and formate. Secondary fermenting organisms (Group 2) degrade fatty acids and alcohols to hydrogen, carbon dioxide, acetate, and formate. Hydrogenotrophic methanogens (Group 3) and acetoclastic methanogens (Group 4) convert carbon dioxide and formate or acetate to methane, respectively. For a more detailed discussion see accompanying text.