Necessity of electrically conductive pili for methanogenesis with magnetite stimulation
In: PeerJ, Vol 6, p e4541 (2018, 2018
Online
academicJournal
Zugriff:
Background Magnetite-mediated direct interspecies electron transfer (DIET) between Geobacter and Methanosarcina species is increasingly being invoked to explain magnetite stimulation of methane production in anaerobic soils and sediments. Although magnetite-mediated DIET has been documented in defined co-cultures reducing fumarate or nitrate as the electron acceptor, the effects of magnetite have only been inferred in methanogenic systems. Methods Concentrations of methane and organic acid were analysed with a gas chromatograph and high-performance liquid chromatography, respectively. The concentration of HCl-extractable Fe(II) was determined by the ferrozine method. The association of the defined co-cultures of G. metallireducens and M. barkeri with magnetite was observed with transmission electron micrographs. Results Magnetite stimulated ethanol metabolism and methane production in defined co-cultures of G. metallireducens and M. barkeri; however, magnetite did not promote methane production in co-cultures initiated with a culture of G. metallireducens that could not produce electrically conductive pili (e-pili), unlike the conductive carbon materials that facilitate DIET in the absence of e-pili. Transmission electron microscopy revealed that G. metallireducens and M. barkeri were closely associated when magnetite was present, as previously observed in G. metallireducens/G. sulfurreducens co-cultures. These results show that magnetite can promote DIET between Geobacter and Methanosarcina species, but not as a substitute for e-pili, and probably functions to facilitate electron transfer from the e-pili to Methanosarcina. Conclusion In summary, the e-pili are necessary for the stimulation of not only G. metallireducens/G. sulfurreducens, but also methanogenic G. metallireducens/M. barkeri co-cultures with magnetite.
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Necessity of electrically conductive pili for methanogenesis with magnetite stimulation
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Autor/in / Beteiligte Person: | Wang, Oumei ; Zheng, Shiling ; Wang, Bingchen ; Wang, Wenjing ; Liu, Fanghua |
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Zeitschrift: | PeerJ, Vol 6, p e4541 (2018, 2018 |
Veröffentlichung: | PeerJ Inc., 2018 |
Medientyp: | academicJournal |
ISSN: | 2167-8359 (print) |
DOI: | 10.7717/peerj.4541 |
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