Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underly...Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underlying microbial ability to exchange electrons with the redox active materials that are external to the microbial cells. The microorganisms with extracellular electron transfer capability are often referred to as exoelectrogens. Although exoelectrogens were documented in early 1900’s, discovery of the dissimilatory metal-reducing microorganisms Geobacter and Shewanella spp. in late 1980’s marked the beginning of modern electromicrobiology. Since then, thorough and rigorous studies have made Geobacter and Shewanella spp. the two best characterized groups of exoelectrogens. These include identification and characterization of the molecular mechanisms for exchanging electrons with electrodes by Geobacter sulfurreducens and Shewanella oneidensis. In addition, a variety of applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis, such as maintenance of redox balance during fermentations and bioremediations, have also been developed. This review briefly discusses the molecular mechanisms by which G. sulfurreducens and S. oneidensis exchange electrons with electrodes and then focuses on biotechnological applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis as well as the future directions of this research area.展开更多
Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter...Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter is less than 10 nm from a trace amount of Au^(3+)concentration at the level of tens ppm.Here,we constructed an exoelectrogenic cell(eCell)-conductive reduced-graphene-oxide aero-gel(rGA)biohybrid by assembling Shewanella sp.S1(SS1)as living biocatalyst and rGA as conductive ad-sorbent,in which Au^(3+)at trace concentrations would be enriched by the adsorption of rGA and reduced to AuNPs through the extracellular electron transfer(EET)of SS1.To regulate the size of the synthe-sized AuNPs to 10 nm,the strain SS1 was engineered to enhance its EET,resulting in strain RS2(pYYD-P tac-ribADEHC&pHG13-P_(bad)-omcC in SS1).Strain RS2 was further assembled with rGA to construct the RS2-rGA biohybrid,which could synthesize AuNPs with the size of 7.62±2.82 nm from 60 ppm Au^(3+)so-lution.The eCell-rGA biohybrid integrated Au^(3+)adsorption and reduction,which enabled AuNPs biosyn-thesis from a trace amount of Au^(3+).Thus,the required Au^(3+)ions concentration was reduced by one or two orders of magnitude compared with conventional methods of AuNPs biosynthesis.Our work devel-oped an AuNPs size regulation technology via engineering eCell’s EET with synthetic biology methods,providing a feasible approach to synthesize AuNPs with controllable size from trace level of gold ions.展开更多
Current methods for testing the electricity generation capacity of isolates are time-and laborconsuming.This paper presents a rapid voltage testing system of exoelectrogenic bacteria called Quickscreen,which is based ...Current methods for testing the electricity generation capacity of isolates are time-and laborconsuming.This paper presents a rapid voltage testing system of exoelectrogenic bacteria called Quickscreen,which is based on a microliter microbial fuel cell(MFC).Geobacter sulfurreducens and Shewanella baltica were used as the model exoelectrogenic bacteria;Escherichia coli that cannot generate electricity was used as a negative control.It was found that the electricity generation capacity of the isolates could be determined within about five hours by using Quickscreen,and that its time was relatively rapid compared with the time needed by using larger MFCs.A parallel,stable,and low background voltage was achieved using titanium as a current collector in the blank run.The external resistance had little impact on the blank run during the initial period.The cathode with a five-hole configuration,used to hydrate the carbon cathode,gave higher cathode potential than that with a one-hole configuration.Steady discharge and current interrupt methods showed that the anode mostly contributed to the large internal resistance of the Quickscreen system.However,the addition of graphite felt decreased the resistance from 18 to 5 kΩ.This device was proved to be useful to rapidly evaluate the electricity generation capacity of different bacteria.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.NSFC91851211&41772363)the One Hundred Talents Program of Hubei Province and China University of Geosciences-Wuhan
文摘Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underlying microbial ability to exchange electrons with the redox active materials that are external to the microbial cells. The microorganisms with extracellular electron transfer capability are often referred to as exoelectrogens. Although exoelectrogens were documented in early 1900’s, discovery of the dissimilatory metal-reducing microorganisms Geobacter and Shewanella spp. in late 1980’s marked the beginning of modern electromicrobiology. Since then, thorough and rigorous studies have made Geobacter and Shewanella spp. the two best characterized groups of exoelectrogens. These include identification and characterization of the molecular mechanisms for exchanging electrons with electrodes by Geobacter sulfurreducens and Shewanella oneidensis. In addition, a variety of applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis, such as maintenance of redox balance during fermentations and bioremediations, have also been developed. This review briefly discusses the molecular mechanisms by which G. sulfurreducens and S. oneidensis exchange electrons with electrodes and then focuses on biotechnological applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis as well as the future directions of this research area.
基金supported by the National Key Research and Development Program of China(No.2018YFA0901300)the Na-tional Natural Science Foundation of China(Nos.NSFC 32071411,NSFC 32001034,and NSFC 31701569)+1 种基金the Young Science and Tech-nology Talents Growth Project of Education Department of Guizhou Province(No.KY[2018]445)Key Laboratory of Wuliangye-flavor Liquor Solid-state Fermentation,China National Light Indus-try(No.2021JJ013).
文摘Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter is less than 10 nm from a trace amount of Au^(3+)concentration at the level of tens ppm.Here,we constructed an exoelectrogenic cell(eCell)-conductive reduced-graphene-oxide aero-gel(rGA)biohybrid by assembling Shewanella sp.S1(SS1)as living biocatalyst and rGA as conductive ad-sorbent,in which Au^(3+)at trace concentrations would be enriched by the adsorption of rGA and reduced to AuNPs through the extracellular electron transfer(EET)of SS1.To regulate the size of the synthe-sized AuNPs to 10 nm,the strain SS1 was engineered to enhance its EET,resulting in strain RS2(pYYD-P tac-ribADEHC&pHG13-P_(bad)-omcC in SS1).Strain RS2 was further assembled with rGA to construct the RS2-rGA biohybrid,which could synthesize AuNPs with the size of 7.62±2.82 nm from 60 ppm Au^(3+)so-lution.The eCell-rGA biohybrid integrated Au^(3+)adsorption and reduction,which enabled AuNPs biosyn-thesis from a trace amount of Au^(3+).Thus,the required Au^(3+)ions concentration was reduced by one or two orders of magnitude compared with conventional methods of AuNPs biosynthesis.Our work devel-oped an AuNPs size regulation technology via engineering eCell’s EET with synthetic biology methods,providing a feasible approach to synthesize AuNPs with controllable size from trace level of gold ions.
基金the National Natural Science Foundation of China(Grant No.20577027)the International Program of MOST(Grant No.2006DFA91120)the National High Technology Research and Development Program of China(863 Program)(Grant No.2006AA06Z329)。
文摘Current methods for testing the electricity generation capacity of isolates are time-and laborconsuming.This paper presents a rapid voltage testing system of exoelectrogenic bacteria called Quickscreen,which is based on a microliter microbial fuel cell(MFC).Geobacter sulfurreducens and Shewanella baltica were used as the model exoelectrogenic bacteria;Escherichia coli that cannot generate electricity was used as a negative control.It was found that the electricity generation capacity of the isolates could be determined within about five hours by using Quickscreen,and that its time was relatively rapid compared with the time needed by using larger MFCs.A parallel,stable,and low background voltage was achieved using titanium as a current collector in the blank run.The external resistance had little impact on the blank run during the initial period.The cathode with a five-hole configuration,used to hydrate the carbon cathode,gave higher cathode potential than that with a one-hole configuration.Steady discharge and current interrupt methods showed that the anode mostly contributed to the large internal resistance of the Quickscreen system.However,the addition of graphite felt decreased the resistance from 18 to 5 kΩ.This device was proved to be useful to rapidly evaluate the electricity generation capacity of different bacteria.
