Methanogenesis

Taking O to be in oxidation state -2, H in state +1 and ignoring all other SOM elements, the charges on SOMo C and SOMi C are therefore 

These equations can be combined to give AZ in terms of 4 = VCH4/VCO2)  

Here b is the number of moles of acetate produced per mole of SOM carbon decomposed. Erom Equation (5.3), the number moles of H2 produced is 

There are various possible explanations for the decrease in oxidation state of the SOM carbon in most of the soils. One is that the SOM comprises different pools of organic matter with carbon in different oxidation states, and Z decreases as a result of preferential oxidation of more-oxidized pools of SOM, leaving a greater proportion of the more-reduced forms in the residue. The more oxidized SOM would include compounds in the original SOM and also compounds generated in the course of reduction, for example as a result of chemical oxidation by Fe(III) and other metal oxides. Alternatively, part of the organic matter could 

CO2 consumed CH4 produced CH4 produced CO2 produced CO2 produced by H2 from H2 + CO2 from acetate from acetate from SOM 

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Methanogenesis from Acetate, Residence Time and Size of Ruminants... 

Emptage M, J Tabinowski, JM Odom (1997) Effect of fluoroacetates on methanogenesis in samples from selected methanogenic environments. Environ Sci Technol 31 732-734. 

These reductases play a key role both in methanogenesis and in the degradation of phenols that carry several nitro groups, which is discussed further in Chapter 9, Part 5. Although these reductases are typically found in methanogens, they have been encountered in a number of other bacteria and archaea ... 

Methanogenesis from CO2 via methenyl H MPT, methylene H MPT, and methyl H MPT using coenzyme F420H2 (5,6,7,8-tetrahydrofolate). 

Sierra-Alvarez R, I Cortinas, U Venal, JA Field (2004) Methanogenesis inhibited by arsenic compounds. Appl Environ Microbiol 70 5688-5691. 

Hallam SJ, N Putnam, CM Preston, JC Detter, D Rokhsar, PM Richardson, EF DeLong (2004) Reverse methanogenesis testing the hypothesis with environmental genomics. Science 305 1457-1462. 

Complete dechlorination of high concentrations of tetrachloroethene in the absence of methanogenesis has been achieved nsing methanol as electron donor (DiStefano et al. 1991). 

DiStefano, TD, JM Gossett, SH Zinder (1991) Reductive dechlorination of high concentrations of tetrachloro-ethene to ethene by an anaerobic enrichment culture in the absence of methanogenesis. Appl Environ Microbiol 57 2287-2292. 

Hess, H. D., Beuret, R. A., Lotscher, M., Hindrichsen, 1. K., Machmiiller, A., Carulla, J. E., Lascano, C. E., and Kreuzer, M. (2004). Ruminal fermentation, methanogenesis and nitrogen utilization of sheep receiving tropical grass hay-concentrate diets offered with Sapindus saponaria fruits and Cratylia argentea foliage. Anim. Sci. 79,177-189. 

Methanogenesis Co2+ 40 pM Methanosarcina sp. Mineral salts medium containing bicarbonate buffer and 1 mM sulfur 66... 

Capone, D.G., Reese, D.D., and Kiene, R.P., Effects of metals on methanogenesis, sulfate reduction, carbon dioxide evolution, and microbial biomass in anoxic salt marsh sediments, Appl Environ Microbiol, 45 (5), 1586-1591, 1983. 

Munoz, M., Codina, J., Vicente, A., Borrego, J., and Morinigo, M., Effects of nickel and lead and a support material on the methanogenesis from sewage sludge, Lett Appl Microbiol, 23 (5), 339-342, 1996. 

Jansen, S., Gonzalez-Gil, G., and Leeuwen, H.P.V., The impact of Co and Ni speciation on methanogenesis in sulfidic media—biouptake versus metal dissolution, Enzyme Microb Technol, 40 (4), 823-830, 2007. 

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