Ecology of methanogenic systems in nature

Decomposition in terrestrial and aquatic environments of biogenic or synthetic organic material to inorganic products (also referred to as ‘mineralization’) is predominantly accomplished by microbial oxidations. Under anaerobic conditions, protons, sulfur or carbon atoms are the exclusive electron sinks, products being H2, H2S or CH4 respectively. In this last case, the hydrogénation of CO2 to CH4 or the protonation of the methyl group in acetate (or methylamins) to CH4 are the final reactions:

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