Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately...Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately in previous studies and it has remained unknown whether methane is able to simultaneously drive these processes.Here we investigated the co-occurrence and performance of these two processes in the anodic chamber of MFCs.The results showed that methane successfully fueled both electrogenesis and denitrification.Importantly,the maximum nitrate removal rate was significantly enhanced from(1.4±0.8)to(18.4±1.2)mg N/(L·day)by an electrogenic process.In the presence of DAMO,the MFCs achieved a maximum voltage of 610 mV and a maximum power density of 143±12 mW/m^(2).Electrochemical analyses demonstrated that some redox substances(e.g.riboflavin)were likely involved in electrogenesis and also in the denitrification process.High-throughput sequencing indicated that the methanogen Methanobacterium,a close relative of Methanobacterium espanolae,catalyzed methane oxidation and cooperated with both exoelectrogens and denitrifiers(e.g.,Azoarcus).This work provides an effective strategy for improving DAMO in methane-powered MFCs,and suggests that methanogens and denitrifiers may jointly be able to provide an alternative to archaeal DAMO for methane-dependent denitrification.展开更多
二氧化碳(CO_2)资源化利用是近年来的一个研究热点,利用生物电化学系统还原CO_2生产能源物质是一种新兴技术.在微生物电合成系统(MES)中利用混合微生物富集阴极功能微生物,评估阴极电势对其还原CO_2产甲烷的影响.当阴极电势从-0.70 V降...二氧化碳(CO_2)资源化利用是近年来的一个研究热点,利用生物电化学系统还原CO_2生产能源物质是一种新兴技术.在微生物电合成系统(MES)中利用混合微生物富集阴极功能微生物,评估阴极电势对其还原CO_2产甲烷的影响.当阴极电势从-0.70 V降低到-0.90 V vs Ag/Ag Cl时,MES产甲烷的量和速率都在增加,最大的产甲烷量和速率分别达到了0.265 mol/m^2和0.025 mmol/h.与此同时,MES的电流密度从0.002 A/m^2增加到0.18 A/m^2,阴极产甲烷的库伦效率在49%和90%之间.当阴极电势更负时,MES阴极几乎不产甲烷.扫描电镜分析(SEM)表明,有多种不同形态的微生物吸附在阴极碳毡上,它们的形态主要呈杆状和球状.16S r DNA测序分析表明Methanobacterium是MES阴极生物膜上优势的产甲烷菌.本研究表明,微生物电合成系统还原CO_2产甲烷的阴极电势必须控制在适当的范围内,才能高效地还原CO_2产甲烷.展开更多
基金supported by the National Natural Science Foundation of China(No.42077284)the Natural Science Foundation of Fujian Province,China(No.2020J02015)the Fund for Outstanding Young Scientific Talent Cultivation Program of Fujian Agriculture and Forestry University of China(No.XJQ201906).
文摘Methane has been demonstrated to be a feasible substrate for electricity generation in microbial fuel cells(MFCs)and denitrifying anaerobic methane oxidation(DAMO).However,these two processes were evaluated separately in previous studies and it has remained unknown whether methane is able to simultaneously drive these processes.Here we investigated the co-occurrence and performance of these two processes in the anodic chamber of MFCs.The results showed that methane successfully fueled both electrogenesis and denitrification.Importantly,the maximum nitrate removal rate was significantly enhanced from(1.4±0.8)to(18.4±1.2)mg N/(L·day)by an electrogenic process.In the presence of DAMO,the MFCs achieved a maximum voltage of 610 mV and a maximum power density of 143±12 mW/m^(2).Electrochemical analyses demonstrated that some redox substances(e.g.riboflavin)were likely involved in electrogenesis and also in the denitrification process.High-throughput sequencing indicated that the methanogen Methanobacterium,a close relative of Methanobacterium espanolae,catalyzed methane oxidation and cooperated with both exoelectrogens and denitrifiers(e.g.,Azoarcus).This work provides an effective strategy for improving DAMO in methane-powered MFCs,and suggests that methanogens and denitrifiers may jointly be able to provide an alternative to archaeal DAMO for methane-dependent denitrification.
文摘二氧化碳(CO_2)资源化利用是近年来的一个研究热点,利用生物电化学系统还原CO_2生产能源物质是一种新兴技术.在微生物电合成系统(MES)中利用混合微生物富集阴极功能微生物,评估阴极电势对其还原CO_2产甲烷的影响.当阴极电势从-0.70 V降低到-0.90 V vs Ag/Ag Cl时,MES产甲烷的量和速率都在增加,最大的产甲烷量和速率分别达到了0.265 mol/m^2和0.025 mmol/h.与此同时,MES的电流密度从0.002 A/m^2增加到0.18 A/m^2,阴极产甲烷的库伦效率在49%和90%之间.当阴极电势更负时,MES阴极几乎不产甲烷.扫描电镜分析(SEM)表明,有多种不同形态的微生物吸附在阴极碳毡上,它们的形态主要呈杆状和球状.16S r DNA测序分析表明Methanobacterium是MES阴极生物膜上优势的产甲烷菌.本研究表明,微生物电合成系统还原CO_2产甲烷的阴极电势必须控制在适当的范围内,才能高效地还原CO_2产甲烷.
