Conventional wastewater treatment facilities lack the appropriate design to abate the presence of antibiotics,which are potential hazards in natural water sources.The use of electroactive bacteria and biochar to elimi...Conventional wastewater treatment facilities lack the appropriate design to abate the presence of antibiotics,which are potential hazards in natural water sources.The use of electroactive bacteria and biochar to eliminate antibiotics has been reported;however,the impact and underlying mechanisms by which biochar enhances the biodegradation of antibiotics by electroactive microorganisms remain unclear.As chloramphenicol exhibits a high degree of toxicity to aquatic organisms,this study investigated the synergistic effect of biochar on the biodegradation of chloramphenicol by electroactive Shewanella oneidensis MR-1.Biochar significantly improved chloramphenicol degradation rates from 36.05%to 70.79%within 24 h by promoting electron transfer processes in S.oneidensis MR-1,a typical electroactive microorganism.This study offers unique insights into the electrochemical properties of biochar,particularly those influenced by pyrolysis temperature,in enhancing the microbial electron transfer processes.Furthermore,the findings demonstrated that biochar not only promotes the growth and activity of electroactive bacteria but also facilitates direct and indirect electron transfer mechanisms,leading to significantly improved antibiotic degradation rates.In summary,biochar is a novel perspective in environmental biotechnology that offers an innovative approach to address the challenge of persistent antibiotics in wastewater treatment.展开更多
Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively disc...Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively discuss the current state of the art and prospects of medium chain fatty acids(MCFAs)production in MES from CO_(2)and organic wastes.Fundamental mechanisms and development of MCFAs production via conventional fermentation are introduced as well.Studies on MCFAs production in MES are summarized,highlighting the strategy of multiple-electron donors(EDs).Challenges for MCFAs production in MES from CO_(2)are presented,and the primary discussions included methanogenesis inhibition,adenosine triphosphate(ATP)limitations of acetogens,and production of limited EDs via solventogenesis.Possible applications of electrochemical approaches to promote the bioconversion of actual waste materials with MCFAs production are analyzed.Finally,future directions are explored,including multi-stage reactions,substrate supply,product extraction,and microbial pathways.展开更多
In this work,microbiologically influenced corrosion(MIC)of 316 L stainless steel(SS)caused by oral microbiota was investigated with HOMINGS 16 S rRNA gene sequencing technology,and electrochemical and surface analysis...In this work,microbiologically influenced corrosion(MIC)of 316 L stainless steel(SS)caused by oral microbiota was investigated with HOMINGS 16 S rRNA gene sequencing technology,and electrochemical and surface analysis techniques.The results showed that oral microbiota from different subjects developed multi-species biofilms with significant differences in structure and composition of bacteria strains on the316 L SS coupons.In the presence of oral microbiota,more severe pitting corrosion and faster dissolution of metallic ions including Ni and Cr were observed.The biofilm considerably decreased the pitting potential of 316 L SS from 1268.0±29.1 mV vs.SCE(abiotic control)to less than 500 mV vs.SCE.The corrosion current density in the presence of oral microbiota from subject 1(115.3±83.3 nA cm^(-2))and subject 2(184.4±162.0 nA cm^(-2))was at least 4 times more than that in the abiotic medium(28.0±2.3 nA cm^(-2)).The electroactive microorganisms with the potential to facilitate corrosion via extracellular electron transfer found in oral microbiota may be mainly responsible for the accelerated corrosion.展开更多
Electroactive microorganisms are integral to biogeochemical cycles through extracellular electron transfer and have potential applications in environmental remediation.However,their long-term competitive interactions ...Electroactive microorganisms are integral to biogeochemical cycles through extracellular electron transfer and have potential applications in environmental remediation.However,their long-term competitive interactions and evolutionary dynamics with non-electroactive microorganisms remain poorly understood.In this study,we conducted a 320-day cultivation experiment in which monocultures of the electroactive Shewanella oneidensis MR-1,the non-electroactive Citrobacter freundii An1,and their cocultures were compared under three single electron acceptor conditions:anaerobic(no exogenous electron acceptor),ferrihydrite,or oxygen.After 320 d,S.oneidensis MR-1 presented the highest relative abundance of 30.94%±0.74%in the ferrihydrite cocultures.S.oneidensis MR-1 maintained ferrihydrite reduction capacity after cultivation under all three conditions,indicating the long-term stability of its extracellular electron transfer.Moreover,no other phenotypic evolution was observed in S.oneidensis MR-1 after ferrihydrite or anaerobic cultivation.In contrast,both monocultured and cocultured S.oneidensis MR-1 exhibited enhanced adaptation to oxygen,characterized by increased growth rates,metabolic activity,and reduced cell aggregation.Notably,substrate consumption increased in monocultures but decreased in cocultures,suggesting an optimization of metabolic efficiency in the latter.Genome sequencing revealed mutations in genes associated with cell division,adenosine triphosphate synthesis,lactate metabolism,and flagellar/pilus expression in S.oneidensis MR-1.Interestingly,the ferrihydrite-adapted groups also exhibited enhanced adaptation to oxygen.83.96%of mutations were shared across all culture systems and enriched in environmental signal-sensing pathways,indicating that parallel genomic evolution facilitated cross-environmental adaptation.Our findings reveal the ecological evolution of electroactive microorganisms in diverse redox environments and establish a foundation for engineering electroactive communities.展开更多
Electroautotrophy-the use of extracellular electrons as the primary energy source for autotrophic metabolism-remains understudied compared to photoautotrophy and chemoautotrophy.Its occurrence in deep-earth and deep-s...Electroautotrophy-the use of extracellular electrons as the primary energy source for autotrophic metabolism-remains understudied compared to photoautotrophy and chemoautotrophy.Its occurrence in deep-earth and deep-sea environments suggests profound implications for astrobiology,yet electroautotrophic microorganisms remain poorly explored.This review synthesizes the discovery of electroautotrophs and current knowledge from laboratory and field studies,including insights from the deep biosphere.We evaluate their ecological roles on Earth and discuss their potential significance in possible lifesupporting ecosystems elsewhere and in life-detection strategies.Finally,we propose six key research priorities to advance the study of electroautotrophy in astrobiological contexts.展开更多
Obtaining electroactive microbes capable of efficient extracellular electron transfer is a large undertaking for the scalability of bio-electrochemical systems.Inevitably,researchers need to pursue the co-modification...Obtaining electroactive microbes capable of efficient extracellular electron transfer is a large undertaking for the scalability of bio-electrochemical systems.Inevitably,researchers need to pursue the co-modification of multiple genes rather than expecting that modification of a single gene would make a significant contribution to improving extracellular electron transfer rates.Base editing has enabled highly-efficient gene deactivation in model electroactive microbe Shewanella oneidensis MR-1.Since multiplexed application of base editing is still limited by its low throughput procedure,we thus here develop a rapid and efficient multiplex base editing system in S.oneidensis.Four approaches to express multiple gRNAs were assessed firstly,and transcription of each gRNA cassette into a monocistronic unit was validated as a more favorable option than transcription of multiple gRNAs into a polycistronic cluster.Then,a smart scheme was designed to deliver one-pot assembly of multiple gRNAs.3,5,and 8 genes were deactivated using this system with editing efficiency of 83.3%,100%and 12.5%,respectively.To offer some nonrepetitive components as alternatives genetic parts of sgRNA cassette,different promoters,handles,and terminators were screened.This multiplex base editing tool was finally adopted to simultaneously deactivate eight genes that were identified as significantly downregulated targets in transcriptome analysis of riboflavin-overproducing strain and control strain.The maximum power density of the multiplex engineered strain HRF(8BE)in microbial fuel cells was 1108.1 mW/m2,which was 21.67 times higher than that of the wild-type strain.This highly efficient multiplexed base editing tool elevates our ability of genome manipulation and combinatorial engineering in Shewanella,and may provide valuable insights in fundamental and applied research of extracellular electron transfer.展开更多
A laminar flow bioelectrochemical systems(BES)was designed and benchmarked using microbial anodes dominated with Geobacter spp.The reactor architecture was based on modeled flow fields,the resulting structure was 3D p...A laminar flow bioelectrochemical systems(BES)was designed and benchmarked using microbial anodes dominated with Geobacter spp.The reactor architecture was based on modeled flow fields,the resulting structure was 3D printed and used for BES manufacturing.Stratification of the substrate availability within the reactor channels led to heterogeneous biomass distribution,with the maximum biomass found mainly in the initial/middle channels.The anode performance was assessed for different hydraulic retention times while coulombic efficiencies of up to 100%(including also hydrogen recycling from the cathode)and current densities of up to 75 μA cm^(-2) at an anode surface to volume ratio of 1770 cm^(2) L^(-1) after 35 days were achieved.This low current density can be clearly attributed to the heterogeneous distributions of biomass and the stratification of the microbial community structure.Further,it was shown that time and space resolved analysis of the reactor microbiomes per channel is feasible using flow cytometry.展开更多
基金National Key R&D Program of China(No.2021YFC3200602)the Key Research and Development Program of Ningxia Hui Autonomous Region of China(No.2023BEG02053)the Shanghai Chengtou Water Group Co.Ltd.Scientific Research Reserve Project(No.KY.WB.23.001).
文摘Conventional wastewater treatment facilities lack the appropriate design to abate the presence of antibiotics,which are potential hazards in natural water sources.The use of electroactive bacteria and biochar to eliminate antibiotics has been reported;however,the impact and underlying mechanisms by which biochar enhances the biodegradation of antibiotics by electroactive microorganisms remain unclear.As chloramphenicol exhibits a high degree of toxicity to aquatic organisms,this study investigated the synergistic effect of biochar on the biodegradation of chloramphenicol by electroactive Shewanella oneidensis MR-1.Biochar significantly improved chloramphenicol degradation rates from 36.05%to 70.79%within 24 h by promoting electron transfer processes in S.oneidensis MR-1,a typical electroactive microorganism.This study offers unique insights into the electrochemical properties of biochar,particularly those influenced by pyrolysis temperature,in enhancing the microbial electron transfer processes.Furthermore,the findings demonstrated that biochar not only promotes the growth and activity of electroactive bacteria but also facilitates direct and indirect electron transfer mechanisms,leading to significantly improved antibiotic degradation rates.In summary,biochar is a novel perspective in environmental biotechnology that offers an innovative approach to address the challenge of persistent antibiotics in wastewater treatment.
基金supported by the National Natural Science Foundation of China(51908131)Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(19K05ESPCT)+1 种基金the Chinese Academy of Sciences(CAS)Key Laboratory of Environmental and Applied Microbiology&Environmental Microbiology Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences(KLCAS-2019-1)the Fujian Provincial Natural Science Foundation of China(2020J01563)。
文摘Microbial electrosynthesis(MES)employs microbial catalysts and electrochemistry to enhance CO_(2)bioconversion to organics with concurrent waste biorefining capability.The aim of this review is to comprehensively discuss the current state of the art and prospects of medium chain fatty acids(MCFAs)production in MES from CO_(2)and organic wastes.Fundamental mechanisms and development of MCFAs production via conventional fermentation are introduced as well.Studies on MCFAs production in MES are summarized,highlighting the strategy of multiple-electron donors(EDs).Challenges for MCFAs production in MES from CO_(2)are presented,and the primary discussions included methanogenesis inhibition,adenosine triphosphate(ATP)limitations of acetogens,and production of limited EDs via solventogenesis.Possible applications of electrochemical approaches to promote the bioconversion of actual waste materials with MCFAs production are analyzed.Finally,future directions are explored,including multi-stage reactions,substrate supply,product extraction,and microbial pathways.
基金financially supported by the National Natural Science Foundation of China(Nos.U2006219,51871050 and51901039)the Natural Science Foundation of Liaoning Province(No.20180510041)+1 种基金the Liaoning Revitalization Talents Program(No.XLYC1907158)the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(Nos.N180205021,N180203019,and N2002019)。
文摘In this work,microbiologically influenced corrosion(MIC)of 316 L stainless steel(SS)caused by oral microbiota was investigated with HOMINGS 16 S rRNA gene sequencing technology,and electrochemical and surface analysis techniques.The results showed that oral microbiota from different subjects developed multi-species biofilms with significant differences in structure and composition of bacteria strains on the316 L SS coupons.In the presence of oral microbiota,more severe pitting corrosion and faster dissolution of metallic ions including Ni and Cr were observed.The biofilm considerably decreased the pitting potential of 316 L SS from 1268.0±29.1 mV vs.SCE(abiotic control)to less than 500 mV vs.SCE.The corrosion current density in the presence of oral microbiota from subject 1(115.3±83.3 nA cm^(-2))and subject 2(184.4±162.0 nA cm^(-2))was at least 4 times more than that in the abiotic medium(28.0±2.3 nA cm^(-2)).The electroactive microorganisms with the potential to facilitate corrosion via extracellular electron transfer found in oral microbiota may be mainly responsible for the accelerated corrosion.
基金supported by the National Natural Science Foundation of China(No.22276183)the Institute of Urban Environment,Chinese Academy of Sciences(No.IUE-JBGS-202212)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.Y2022082).
文摘Electroactive microorganisms are integral to biogeochemical cycles through extracellular electron transfer and have potential applications in environmental remediation.However,their long-term competitive interactions and evolutionary dynamics with non-electroactive microorganisms remain poorly understood.In this study,we conducted a 320-day cultivation experiment in which monocultures of the electroactive Shewanella oneidensis MR-1,the non-electroactive Citrobacter freundii An1,and their cocultures were compared under three single electron acceptor conditions:anaerobic(no exogenous electron acceptor),ferrihydrite,or oxygen.After 320 d,S.oneidensis MR-1 presented the highest relative abundance of 30.94%±0.74%in the ferrihydrite cocultures.S.oneidensis MR-1 maintained ferrihydrite reduction capacity after cultivation under all three conditions,indicating the long-term stability of its extracellular electron transfer.Moreover,no other phenotypic evolution was observed in S.oneidensis MR-1 after ferrihydrite or anaerobic cultivation.In contrast,both monocultured and cocultured S.oneidensis MR-1 exhibited enhanced adaptation to oxygen,characterized by increased growth rates,metabolic activity,and reduced cell aggregation.Notably,substrate consumption increased in monocultures but decreased in cocultures,suggesting an optimization of metabolic efficiency in the latter.Genome sequencing revealed mutations in genes associated with cell division,adenosine triphosphate synthesis,lactate metabolism,and flagellar/pilus expression in S.oneidensis MR-1.Interestingly,the ferrihydrite-adapted groups also exhibited enhanced adaptation to oxygen.83.96%of mutations were shared across all culture systems and enriched in environmental signal-sensing pathways,indicating that parallel genomic evolution facilitated cross-environmental adaptation.Our findings reveal the ecological evolution of electroactive microorganisms in diverse redox environments and establish a foundation for engineering electroactive communities.
文摘Electroautotrophy-the use of extracellular electrons as the primary energy source for autotrophic metabolism-remains understudied compared to photoautotrophy and chemoautotrophy.Its occurrence in deep-earth and deep-sea environments suggests profound implications for astrobiology,yet electroautotrophic microorganisms remain poorly explored.This review synthesizes the discovery of electroautotrophs and current knowledge from laboratory and field studies,including insights from the deep biosphere.We evaluate their ecological roles on Earth and discuss their potential significance in possible lifesupporting ecosystems elsewhere and in life-detection strategies.Finally,we propose six key research priorities to advance the study of electroautotrophy in astrobiological contexts.
基金supported by the National Key Research and Development Program of China (2018YFA0901300)the National Natural Science Foundation of China (NSFC 32071411,NSFC 22078240,and NSFC 21621004)the Young Elite Scientists Sponsorship Program by Tianjin (TJSQNTJ-2018-16).
文摘Obtaining electroactive microbes capable of efficient extracellular electron transfer is a large undertaking for the scalability of bio-electrochemical systems.Inevitably,researchers need to pursue the co-modification of multiple genes rather than expecting that modification of a single gene would make a significant contribution to improving extracellular electron transfer rates.Base editing has enabled highly-efficient gene deactivation in model electroactive microbe Shewanella oneidensis MR-1.Since multiplexed application of base editing is still limited by its low throughput procedure,we thus here develop a rapid and efficient multiplex base editing system in S.oneidensis.Four approaches to express multiple gRNAs were assessed firstly,and transcription of each gRNA cassette into a monocistronic unit was validated as a more favorable option than transcription of multiple gRNAs into a polycistronic cluster.Then,a smart scheme was designed to deliver one-pot assembly of multiple gRNAs.3,5,and 8 genes were deactivated using this system with editing efficiency of 83.3%,100%and 12.5%,respectively.To offer some nonrepetitive components as alternatives genetic parts of sgRNA cassette,different promoters,handles,and terminators were screened.This multiplex base editing tool was finally adopted to simultaneously deactivate eight genes that were identified as significantly downregulated targets in transcriptome analysis of riboflavin-overproducing strain and control strain.The maximum power density of the multiplex engineered strain HRF(8BE)in microbial fuel cells was 1108.1 mW/m2,which was 21.67 times higher than that of the wild-type strain.This highly efficient multiplexed base editing tool elevates our ability of genome manipulation and combinatorial engineering in Shewanella,and may provide valuable insights in fundamental and applied research of extracellular electron transfer.
基金financed by the German Federal Ministry of Education and Research(BMBF)under the ElektroPapier project(Grant nr:03XP0041G)supported by the Helmholtz-Association within the Research Programme Renewable Energies.
文摘A laminar flow bioelectrochemical systems(BES)was designed and benchmarked using microbial anodes dominated with Geobacter spp.The reactor architecture was based on modeled flow fields,the resulting structure was 3D printed and used for BES manufacturing.Stratification of the substrate availability within the reactor channels led to heterogeneous biomass distribution,with the maximum biomass found mainly in the initial/middle channels.The anode performance was assessed for different hydraulic retention times while coulombic efficiencies of up to 100%(including also hydrogen recycling from the cathode)and current densities of up to 75 μA cm^(-2) at an anode surface to volume ratio of 1770 cm^(2) L^(-1) after 35 days were achieved.This low current density can be clearly attributed to the heterogeneous distributions of biomass and the stratification of the microbial community structure.Further,it was shown that time and space resolved analysis of the reactor microbiomes per channel is feasible using flow cytometry.
