title: Predominant contribution of syntrophic acetate oxidation to thermophilic methane formation at high acetate concentrations.
abstract: To quantify the contribution of syntrophic acetate oxidation to thermophilic anaerobic methanogenesis under the stressed condition induced by acidification, the methanogenic conversion process of 100 mmol/L acetate was monitored simultaneously by using isotopic tracing and selective inhibition techniques, supplemented with the analysis of unculturable microorganisms. Both quantitative methods demonstrated that, in the presence of aceticlastic and hydrogenotrophic methanogens, a large percentage of methane (up to 89%) was initially derived from CO(2) reduction, indicating the predominant contribution of the syntrophic acetate oxidation pathway to acetate degradation at high acid concentrations. A temporal decrease of the fraction of hydrogenotrophic methanogenesis from more than 60% to less than 40% reflected the gradual prevalence of the aceticlastic methanogenesis pathway along with the reduction of acetate. This apparent discrimination of acetate methanization pathways highlighted the importance of the syntrophic acetate-oxidizing bacteria to initialize methanogenesis from high organic loadings.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, PR China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Hao
authors.forename: Fan
authors.initials: F
authors.lastname: Lü
authors.forename: Pin-Jing
authors.initials: PJ
authors.lastname: He
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Shao
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D020387:Food Chain; D008697:Methane / Q000378:metabolism*; D056265:Microbial Interactions; D010084:Oxidation-Reduction; D013696:Temperature
chemical_list: D000085:Acetates; D002245:Carbon Dioxide; D008697:Methane