PeerJ | |
Necessity of electrically conductive pili for methanogenesis with magnetite stimulation | |
article | |
Oumei Wang1  Shiling Zheng2  Bingchen Wang2  Wenjing Wang2  Fanghua Liu2  | |
[1] Binzhou Medical University;Key Laboratory of Coastal Biology and Biological Resources Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences;University of Chinese Academy of Sciences | |
关键词: Geobacter metallireducens; Methanosarcina barkeri; Electrically conductive pili (e-pili); Direct interspecies electron transfer (DIET); Magnetite; Ferrous iron; Ethanol metabolism; Stimulation; Co-cultures; Methane; | |
DOI : 10.7717/peerj.4541 | |
学科分类:社会科学、人文和艺术(综合) | |
来源: Inra | |
【 摘 要 】
BackgroundMagnetite-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.MethodsConcentrations 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.ResultsMagnetite 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.ConclusionIn 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.
【 授权许可】
CC BY
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