Elucidation of metabolic pathways during municipal solid waste anaerobic digestion using methane stable carbon isotope composition and fluorescent in situ hybridization
Résumé
Reconstituted French municipal solid wastes were incubated anaerobically under mesophilic conditions (35°C). Standard physicochemical parameters were monitored together with CH4 and CO2 stable carbon isotopic signatures. As methanogenesis from H2/CO2 results in a larger fractionation against 13C than aceticlastic methanogenesis, methane stable carbon isotope composition (δ13C) can be used to differentiate those two different methanogenic metabolic pathways. CH4 stable carbon isotope composition evolution indicated a change of methanogenic metabolism during the anaerobic digestion of municipal solid wastes. The same metabolic pathways succession was observed in different incubations using different inocula (sewage sludge, landfill leachate). Fluorescent in situ hybridization (FISH) observations were performed during those experiments in order to monitor archaeal populations. Members of the family Methanosarcinaceae were mainly methanogens involved in methane production