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Jing X, Chen S, Liu X, Yang Y, Rensing C, Zhou S. Potassium channel mediates electroactive biofilm formation via recruiting planktonic Geobacter cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:158035. [PMID: 35981588 DOI: 10.1016/j.scitotenv.2022.158035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/31/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Potassium (K+)-channel-based electrical signaling can coordinate microbial actions at a distance that provides an evolutionary advantage to cell communities. Electroactive cells are usually cultured surrounded by an electric field which provided stronger electrical signaling than the K+-mediated electrical signaling. Whether the K+ signaling also plays a role in coordinating the behavior of electroactive microorganisms has not been accurately demonstrated. Thus, we constructed a K+-channel-deficient strain ΔgsuK of Geobacter sulfurreducens to directly investigate roles of K+ signaling in electroactive biofilm formation for the first time. The ΔgsuK strain exhibited significantly inferior biofilm formation (i.e., biomass, thickness and component) and consequently showed weaker electrical performance (i.e., start-up time, current output, electrochemical catalytic behavior and charge transfer resistance) than the wild-type strain. Individual electric generation capacity and the expression of genes involved in biofilm formation and electrical performance in the single cell did not significantly change with the deletion of gsuK, indicating that K+ signaling indeed influenced the recruiting behavior of planktonic cell but not the functioning of the single cell related to biofilm formation or electric generation. This study is intended to provide an in-depth understanding of electroactive biofilm formation and serve as a basis for optimizing its electrical performance via strengthening the recruitment behavior.
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Affiliation(s)
- Xianyue Jing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shanshan Chen
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuting Yang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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2
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Kuruvinashetti K, Kornienko N. Pushing the methodological envelope in understanding the photo/electrosynthetic materials-microorganism interface. iScience 2021; 24:103049. [PMID: 34553134 PMCID: PMC8441150 DOI: 10.1016/j.isci.2021.103049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Biohybrid photo/electrosynthetic systems synergize microbial metabolic pathways and inorganic materials to generate the fuels and chemicals to power our society. They aim to combine the strengths of product selectivity from biological cells and efficient charge generation and light absorption of inorganic materials. However crucial mechanistic questions still remain. In this review we address significant knowledge gaps that must be closed and recent efforts to do so to push biohybrid systems closer to applicability. In particular, we focus on noteworthy advances that have recently been made in applying state-of-the-art analytical spectroscopic, electrochemical, and microelectronic techniques to help pinpoint key complexities of the microbe-materials interface. We discuss the basic function of these techniques, how they have been translated over to study biohybrid systems, and which key insights and implications have been extracted. Finally, we delve into the key advances necessary for the design of next generation biohybrid energy conversion systems.
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Affiliation(s)
- Kiran Kuruvinashetti
- Department of Chemistry, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3 Canada
| | - Nikolay Kornienko
- Department of Chemistry, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3 Canada
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3
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Iannaci A, Myles A, Philippon T, Barrière F, Scanlan EM, Colavita PE. Controlling the Carbon-Bio Interface via Glycan Functional Adlayers for Applications in Microbial Fuel Cell Bioanodes. Molecules 2021; 26:4755. [PMID: 34443344 PMCID: PMC8400688 DOI: 10.3390/molecules26164755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 11/17/2022] Open
Abstract
Surface modification of electrodes with glycans was investigated as a strategy for modulating the development of electrocatalytic biofilms for microbial fuel cell applications. Covalent attachment of phenyl-mannoside and phenyl-lactoside adlayers on graphite rod electrodes was achieved via electrochemically assisted grafting of aryldiazonium cations from solution. To test the effects of the specific bio-functionalities, modified and unmodified graphite rods were used as anodes in two-chamber microbial fuel cell devices. Devices were set up with wastewater as inoculum and acetate as nutrient and their performance, in terms of output potential (open circuit and 1 kΩ load) and peak power output, was monitored over two months. The presence of glycans was found to lead to significant differences in startup times and peak power outputs. Lactosides were found to inhibit the development of biofilms when compared to bare graphite. Mannosides were found, instead, to promote exoelectrogenic biofilm adhesion and anode colonization, a finding that is supported by quartz crystal microbalance experiments in inoculum media. These differences were observed despite both adlayers possessing thickness in the nm range and similar hydrophilic character. This suggests that specific glycan-mediated bioaffinity interactions can be leveraged to direct the development of biotic electrocatalysts in bioelectrochemical systems and microbial fuel cell devices.
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Affiliation(s)
- Alessandro Iannaci
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin, College Green, Dublin 2, Ireland; (A.I.); (A.M.)
| | - Adam Myles
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin, College Green, Dublin 2, Ireland; (A.I.); (A.M.)
| | - Timothé Philippon
- Institut des Sciences Chimiques de Rennes-UMR 6226, CNRS, Univ Rennes, F-35000 Rennes, France;
| | - Frédéric Barrière
- Institut des Sciences Chimiques de Rennes-UMR 6226, CNRS, Univ Rennes, F-35000 Rennes, France;
| | - Eoin M. Scanlan
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin, College Green, Dublin 2, Ireland; (A.I.); (A.M.)
| | - Paula E. Colavita
- School of Chemistry, CRANN and AMBER Research Centres, Trinity College Dublin, College Green, Dublin 2, Ireland; (A.I.); (A.M.)
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4
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Speers AM, Reguera G. Competitive advantage of oxygen-tolerant bioanodes of Geobacter sulfurreducens in bioelectrochemical systems. Biofilm 2021; 3:100052. [PMID: 34222855 PMCID: PMC8242959 DOI: 10.1016/j.bioflm.2021.100052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 10/31/2022] Open
Abstract
Oxidative stress greatly limits current harvesting from anode biofilms in bioelectrochemical systems yet insufficient knowledge of the antioxidant responses of electricigens prevents optimization. Using Geobacter sulfurreducens PCA as a model electricigen, we demonstrated enhanced oxygen tolerance and reduced electron losses as the biofilms grew in height on the anode. To investigate the molecular basis of biofilm tolerance, we developed a genetic screening and isolated 11 oxygen-tolerant (oxt) strains from a library of transposon-insertion mutants. The aggregative properties of the oxt mutants promoted biofilm formation and oxygen tolerance. Yet, unlike the wild type, none of the mutants diverted respiratory electrons to oxygen. Most of the oxt mutations inactivated pathways for the detoxification of reactive oxygen species that could have triggered compensatory chronic responses to oxidative stress and inhibit aerobic respiration. One of the mutants (oxt10) also had a growth advantage with Fe(III) oxides and during the colonization of the anode electrode. The enhanced antioxidant response in this mutant reduced the system's start-up and promoted current harvesting from bioanodes even in the presence of oxygen. These results highlight a hitherto unknown role of oxidative stress responses in the stability and performance of current-harvesting biofilms of G. sulfurreducens and identify biological and engineering approaches to grow electroactive biofilms with the resilience needed for practical applications.
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Affiliation(s)
- Allison M Speers
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
| | - Gemma Reguera
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
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5
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Miran W, Naradasu D, Okamoto A. Pathogens electrogenicity as a tool for in-situ metabolic activity monitoring and drug assessment in biofilms. iScience 2021; 24:102068. [PMID: 33554070 PMCID: PMC7859304 DOI: 10.1016/j.isci.2021.102068] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Concerns regarding increased antibiotic resistance arising from the emergent properties of biofilms have spurred interest in the discovery of novel antibiotic agents and techniques to directly estimate metabolic activity in biofilms. Although a number of methods have been developed to quantify biofilm formation, real-time quantitative assessment of metabolic activity in label-free biofilms remains a challenge. Production of electrical current via extracellular electron transport (EET) has recently been found in pathogens and appears to correlate with their metabolic activity. Accordingly, monitoring the production of electrical currents as an indicator of cellular metabolic activity in biofilms represents a new direction for research aiming to assess and screen the effects of antimicrobials on biofilm activity. In this article, we reviewed EET-capable pathogens and the methods to monitor biofilm activity to discuss advantages of using the capability of pathogens to produce electrical currents and effective combination of these methods. Moreover, we discussed EET mechanisms by pathogenic and environmental bacteria and open questions for the physiological roles of EET in pathogen's biofilm. The present limitations and possible future directions of in situ biofilm metabolic activity assessment for large-scale screening of antimicrobials are also discussed.
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Affiliation(s)
- Waheed Miran
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Divya Naradasu
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 13 West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
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Leininger A, Yates MD, Ramirez M, Kjellerup B. Biofilm structure, dynamics, and ecology of an upscaled biocathode wastewater microbial fuel cell. Biotechnol Bioeng 2020; 118:1305-1316. [PMID: 33305821 DOI: 10.1002/bit.27653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 10/12/2020] [Accepted: 11/21/2020] [Indexed: 11/05/2022]
Abstract
A microbial fuel cell (MFC) system containing modular half-submerged biocathode was operated for 6 months in an 800 L flow-through system with domestic wastewater. For the first time, spatial and temporal differences in biofilm communities were examined on large three-dimensional electrodes in a wastewater MFC. Biocathode microbial community analysis showed a specialized biofilm community with electrogenic and electrotrophic taxa forming during operation, suggesting potentially opposing electrode reactions. The anodic community structure shifted during operation, but no spatial differences were observed along the length of the electrode. Power output from the system was most strongly influenced by pH. Higher power densities were associated with the use of solids-dewatering filtrate with increased organic matter, conductivity, and pH. The results show that the biocathode was the rate-limiting step and that future MFC design should consider the effect of size, shape, and orientation of biocathodes on their community assembly and electrotrophic ability.
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Affiliation(s)
- Aaron Leininger
- Department of Civil and Environmental Engineering, University of Maryland, College Park, Maryland, USA
| | - Matthew D Yates
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, District of Columbia, USA
| | - Mark Ramirez
- DC Water Blue Plains, Resource Recovery, Washington, District of Columbia, USA
| | - Birthe Kjellerup
- Department of Civil and Environmental Engineering, University of Maryland, College Park, Maryland, USA
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7
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Sievers P, Johannsmann D. Environmental-Stress-Induced Increased Softness of Electroactive Biofilms, Determined with a Torsional Quartz Crystal Microbalance. Anal Chem 2019; 91:14476-14481. [PMID: 31610643 DOI: 10.1021/acs.analchem.9b03204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electroactive biofilms are intensely studied not only for energy conversion and electrosynthesis, but also as sensing systems. The electrical current produced by the layer is largely proportional to the rate of metabolism and therefore decreases when the biofilm experiences adverse environmental conditions. Acoustic measurements may complement this approach. The layer's softness can be inferred from shifts of resonance frequency and resonance bandwidth of a quartz crystal microbalance (QCM) contacting these layers. The layer's softness responds to the environment. Both negative potentials of the electrode (the equivalent of "suffocation") and lack of nutrient supply (the equivalent of "starvation") were studied. For comprehensive analysis, torsional resonators operating on three different modes of vibration are suited best. Such data can be fitted with a viscoelastic model, leading to a quantitative estimate of the shear modulus. On a more empirical level, one might also use the ratio of the shift in bandwidth to the negative shift in frequency as an indicator of stress. For ease of operation, one might even replace the torsional resonators with thickness-shear resonators.
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Affiliation(s)
- Philipp Sievers
- Institute of Physical Chemistry , Clausthal University of Technology , 38678 Clausthal-Zellerfeld , Germany
| | - Diethelm Johannsmann
- Institute of Physical Chemistry , Clausthal University of Technology , 38678 Clausthal-Zellerfeld , Germany
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Jones AAD, Buie CR. Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport. Sci Rep 2019; 9:2602. [PMID: 30796283 PMCID: PMC6385357 DOI: 10.1038/s41598-019-39267-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/28/2018] [Indexed: 11/09/2022] Open
Abstract
Electroactive bacteria such as Geobacter sulfurreducens and Shewanella onedensis produce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because their electron acceptor is always accessible. In bioelectrochemical systems such as microbial fuel cells, corrosion-resistant metals uptake current from the bacteria, producing power. While beneficial for engineering applications, collecting current using corrosion resistant metals induces pH stress in the biofilm, unlike the naturally occurring process where a reduced metal combines with protons released during respiration. To reduce pH stress, some bioelectrochemical systems use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convective transport, thus, reducing pH stress in these systems remains a challenge. Understanding how convection is necessary but not sufficient for maintaining biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). In this study we use a rotating disc electrode to emulate a practical bioelectrochemical system, while decoupling mass transport from shear stress. This is the first study to isolate the metabolic and structural changes in electroactive biofilms due to shear stress. We find that increased shear stress reduces biofilm development time while increasing its metabolic rate. Furthermore, we find biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases. These results not only provide guidelines for improving performance of bioelectrochemical systems, but also reveal features of biofilm behavior. Results of this study suggest that optimized reactors may initiate operation at high shear to decrease development time before decreasing shear for steady-state operation. Furthermore, this biofilm memory discovered will help explain the presence of channels within biofilms observed in other studies.
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Affiliation(s)
- A-Andrew D Jones
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Chemical Engineering and Department of Mechanical & Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Cullen R Buie
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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9
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Sievers P, Moß C, Schröder U, Johannsmann D. Use of torsional resonators to monitor electroactive biofilms. Biosens Bioelectron 2018; 110:225-232. [PMID: 29625330 DOI: 10.1016/j.bios.2018.03.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/05/2018] [Accepted: 03/20/2018] [Indexed: 01/08/2023]
Abstract
Whereas the study of interfaces and thin films with the quartz crystal microbalance (QCM) is well established, biofilms have proven to be a difficult subject for the QCM. The main problem is that the shear wave emanating from the resonator surface does not usually reach to the top of the sample. This problem can be solved with torsional resonators. These have a resonance frequency in the range of tens of kHz, which is much below the frequency of the thickness-shear QCMs. The depth of penetration of the shear wave is correspondingly larger. Data acquisition and data analysis can proceed in analogy to the conventional thickness-shear QCM. Torsional resonators may also be operated as electrochemical QCMs (EQCMs), meaning that a DC electrical potential may be applied to the active electrode and that shifts of frequency and bandwidth may be acquired in parallel to the electrical current. Here we report on the formation of mixed-culture biofilms dominated by the microorganism Geobacter anodireducens. The viscoelastic analysis evidences an increase in rigidity as the films grows. Potential sweeps on electroactive biofilms reveal a softening under negative potentials, that is, under conditions, where the layer's metabolism was slowed down by insufficient oxidative activity of the substrate. For comparison, biofilms were monitored in parallel with a conventional thickness-shear QCM.
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Affiliation(s)
- Phillipp Sievers
- Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str. 4, D-38678 Clausthal-Zellerfeld, Germany
| | - Christopher Moß
- Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
| | - Uwe Schröder
- Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
| | - Diethelm Johannsmann
- Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str. 4, D-38678 Clausthal-Zellerfeld, Germany; Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany.
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10
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Engineering of Microbial Electrodes. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 167:135-180. [PMID: 28864879 DOI: 10.1007/10_2017_16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter provides an overview of the current state-of-the-art in the engineering of microbial electrodes for application in microbial electrosynthesis. First, important functional aspects and requirements of basic materials for microbial electrodes are introduced, including the meaningful benchmarking of electrode performance, a comparison of electrode materials, and methods to improve microbe-electrode interaction. Suitable current collectors and composite materials that combine different functionalities are also discussed. Subsequently, the chapter focuses on the design of macroscopic electrode structures. Aspects such as mass transfer and electrode topology are touched upon, and a comparison of the performance of microbial electrodes relevant for practical application is provided. The chapter closes with an overall conclusion and outlook, highlighting the future prospects and challenges for the engineering of microbial electrodes toward practical application in the field of microbial electrosynthesis. Graphical Abstract.
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PENG L, ZHANG XT, KAWAICHI S, XIE DT, LI ZL. Using Acetate and Formate as the Substrates for Geobacter sulfurreducens Exoelectrogenesis Resulted in Different Half-saturation Potentials. ELECTROCHEMISTRY 2015. [DOI: 10.5796/electrochemistry.83.600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Luo PENG
- School of Resources & Environment, Southwest University
- Biofunctional Catalysts Research Team, RIKEN Center for Sustainable Resource Science
| | | | - Satoshi KAWAICHI
- Biofunctional Catalysts Research Team, RIKEN Center for Sustainable Resource Science
| | - De-Ti XIE
- School of Resources & Environment, Southwest University
| | - Zhen-Lun LI
- School of Resources & Environment, Southwest University
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