Syntrophic Methanogenesis in a Lake Sediment was Facilitated by Conductive Fe3O4 Nanoparticles and Multi-walled Carbon Nanotubes
Syntrophic methanogenesis is an essential link in the carbon cycle in anoxic environments like wetlands and sediments.Interspecies electron transfer(IET)via diffusive carriers(e.g.hydrogen and formate)has been considered to be crucial in this process.Recent studies,however,reveal the presence of direct interspecies electron transfer(DIET)in methanogenesis occurring in anaerobic digesters,paddy soils,and laboratory co-cultures.Here,we evaluated the possible involvement of DIET in the syntrophic oxidation of propionate in the enrichments obtained from an urban lake sediment.The results showed that the production of CH4 was significantly accelerated in the presence of conductive nanoscale Fe3O4 and multi-walled carbon nanotubes in the sediment enrichments.Observations by fluorescence in situ hybridization and scanning electron microscope indicated that microbial aggregates were formed in the enrichments.It appeared that the average cell-to-cell distance in aggregates in nanomaterial-amended enrichments was larger than that in aggregates in the non-amended control.These results suggested that the canonical IET via H2/formate diffusion might not be the sole pathway for the syntrophic interaction.Instead,DIET-mediated syntrophic methanogenesis could occur in the lake sediments in the presence of conductive materials.Microbial community analysis of the enrichments revealed that the genera of Syntrophomonas,Syntrophus,Methanoregula,and Methanosarcina were responsible for syntrophic oxidation of propionate in lake sediment samples.The mechanism for the conductive-materialfacilitated DIET in propionate syntrophy deserves further investigation.
syntrophy methanogenesis direct interspecies electron transfer Fe3O4 MWNT propionate
Xingxuan Xia Jianchao Zhang Tianze Song Yahai Lu
College of Urban and Environmental Sciences,Peking University,Beijing,China
国际会议
The 11th International Symposium on Geochemistry of the Earths Surface(GES-11)(第十一届地球表层地球化学国际研讨会)
贵阳
英文
1-7
2017-06-11（万方平台首次上网日期，不代表论文的发表时间）