Enrichment of thermophilic propionate-oxidizing bacteria in syntrophy with Methanobacterium thermoautotrophicum or Methanobacterium thermoformicicum
TLDR
Results indicate that formate inhibited succinate oxidation to fumarate, an intermediate step in the biochemical pathway of propionate oxidation in cultures with M. thermoautotrophicum, showing that interspecies hydrogen transfer is the mechanism by which reducing equivalents are channelled from the acetogens to this methanogen.Abstract:
Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture of volatile fatty acids as feed. Thermophilic hydrogenotrophic methanogens had a high decay rate. Therefore, stable, thermophilic propionate-oxidizing cultures could not be obtained by using the usual enrichment procedures. Stable and reproducible cultivation was possible by enrichment in hydrogen-pregrown cultures of Methanobacterium thermoautotrophicum ΔH which were embedded in precipitates of FeS, achieved by addition of FeCl2 to the media. The propionate-oxidizing bacteria formed spores which resisted pasteurization for 30 min at 90°C or 10 min at 100°C. Highly purified cultures were obtained with either M. thermoautotrophicum ΔH or Methanobacterium thermoformicicum Z245 as the syntrophic partner organism. The optimum temperature for the two cultures was 55°C. Maximum specific growth rates of cultures with M. thermoautotrophicum ΔH were somewhat lower than those of cultures with M. thermoformicicum Z245 (0.15 and 0.19 day-1, respectively). Growth rates were even higher (0.32 day-1) when aceticlastic methanogens were present as well. M. thermoautotrophicum ΔH is an obligately hydrogen-utilizing methanogen, showing that interspecies hydrogen transfer is the mechanism by which reducing equivalents are channelled from the acetogens to this methanogen. Boundaries of hydrogen partial pressures at which propionate oxidation occurred were between 6 and 34 Pa. Formate had a strong inhibitory effect on propionate oxidation in cultures with M. thermoautotrophicum. Inhibition by formate was neutralized by addition of the formate-utilizing methanogen or by addition of fumarate. Results indicate that formate inhibited succinate oxidation to fumarate, an intermediate step in the biochemical pathway of propionate oxidation.read more
Citations
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Journal ArticleDOI
Energetics of syntrophic cooperation in methanogenic degradation.
TL;DR: S syntrophically fermenting bacteria synthesize ATP by substrate-level phosphorylation and reinvest part of the ATP-bound energy into reversed electron transport processes, to release the electrons at a redox level accessible by the partner bacteria and to balance their energy budget.
Journal ArticleDOI
Electron transfer in syntrophic communities of anaerobic bacteria and archaea
TL;DR: The transfer of hydrogen and formate between bacteria and archaea that helps to sustain growth in syntrophic methanogenic communities is reviewed and the process of reverse electron transfer is described, which is a key requirement in obligately syntrophic interactions.
Book ChapterDOI
Physiological Ecology of Methanogens
TL;DR: Biological methanogenesis plays a major role in the carbon cycle on Earth and is the terminal step in carbon flow in many anaerobic habitats, including marine and freshwater sediments, marshes and swamps, flooded soils, bogs, geothermal habitats, and animal gastrointestinal tracts as discussed by the authors.
Journal ArticleDOI
Metabolic interactions between anaerobic bacteria in methanogenic environments.
TL;DR: Syntrophic relationships which depend on interspecies hydrogen or formate transfer were described for the degradation of e.g. fatty acids, amino acids and aromatic compounds in methanogenic environments.
Journal ArticleDOI
Anaerobic codigestion of municipal solid waste and biosolids under various mixing conditions-II : microbial population dynamics
TL;DR: Mixing appears to inhibit the syntrophic oxidation of volatile fatty acids, possibly by disrupting the spatial juxtaposition of syntrophic bacteria and their methanogenic partners.
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Propionate-Degrading Bacterium, Syntrophobacter wolinii sp. nov. gen. nov., from Methanogenic Ecosystems
David R. Boone,Marvin P. Bryant +1 more
TL;DR: A new genus and species of a nonmotile gram-negative rod, Syntrophobacter wolinii, is the first bacterium described which degrades propionate only in coculture with an H(2)-using organism and in the absence of light or exogenous electron acceptors such as O(2), sulfate, or nitrate.
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TL;DR: Three strains of the bacterium were characterized and are described as a new genus and species, Syntrophomonas wolfei, which contains poly-beta-hydroxybutyrate, and the presence of muramic acid, inhibition of growth by penicillin, and increased sensitivity of the cells to lysis after treatment with lysozyme indicate that peptidoglycan is present in the cell wall.
Journal ArticleDOI
Anaerobic bacterium that degrades fatty acids in syntrophic association with methanogens
TL;DR: A new species of anaerobic bacterium that degrades the even-numbered carbon fatty acids, butyrate, caproate and caprylate, to acetate and H2 and the odd- numbered carbon fatty acid, valerate and heptanoate, toacetate, propionate andH2 was obtained in coculture with either an H2-utilizing methanogen or H2 -utilizing desulfovibrio.
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