title: Evidence of anaerobic syntrophic acetate oxidation in biogas batch reactors by analysis of 13C carbon isotopes.
abstract: Between 2008 and 2010 various batch experiments were carried out to study the stable carbon isotopic composition of biogas (CH4 and CO2) produced from (i) pure sludge and (ii) sludge including maize. From the evolution of the natural isotopic signature, a temporal change of methanogenic pathways could be detected for the treatment with maize showing that a dominance in acetotrophic methanogenesis was replaced by a mixture of hydrogenotrophic and acetotrophic methanogenesis. For pure sludge, hydrogenotrophic methanogenesis was the dominant or probably exclusive pathway. Experiments with isotopically labelled acetate (99% (13)CH3COONa and 99% CH3(13)COONa) indicated a significant contribution of syntrophic acetate oxidation (SAO) for all the investigated treatments. In the case of pure sludge, experiments from 2008 showed that acetate was almost entirely oxidised to CO2, i.e. acetotrophic methanogenesis was negligible. However, in 2010, the sludge showed a clear dominance in acetotrophic methanogenesis with a minor contribution by SAO indicating a significant change in the metabolic character. Our results indicate that SAO during anaerobic degradation of maize might be a significant process that needs to be considered in biogas research.
authors.affiliation: a Max-Planck-Institute for Chemistry , Mainz , Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Polag
authors.forename: Hauke
authors.initials: H
authors.lastname: Heuwinkel
authors.forename: Stephan
authors.initials: S
authors.lastname: Laukenmann
authors.forename: Markus
authors.initials: M
authors.lastname: Greule
authors.forename: Frank
authors.initials: F
authors.lastname: Keppler
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis*; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes / Q000032:analysis* / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D008697:Methane / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D056804:Biofuels; D002247:Carbon Isotopes; D012722:Sewage; D002245:Carbon Dioxide; D008697:Methane; D019342:Acetic Acid