1
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Nguyen HTT, Le GTH, Park SG, Jadhav DA, Le TTQ, Kim H, Vinayak V, Lee G, Yoo K, Song YC, Chae KJ. Optimizing electrochemically active microorganisms as a key player in the bioelectrochemical system: Identification methods and pathways to large-scale implementation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169766. [PMID: 38181955 DOI: 10.1016/j.scitotenv.2023.169766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/15/2023] [Accepted: 12/28/2023] [Indexed: 01/07/2024]
Abstract
The rapid global economic growth driven by industrialization and population expansion has resulted in significant issues, including reliance on fossil fuels, energy scarcity, water crises, and environmental emissions. To address these issues, bioelectrochemical systems (BES) have emerged as a dual-purpose solution, harnessing electrochemical processes and the capabilities of electrochemically active microorganisms (EAM) to simultaneously recover energy and treat wastewater. This review examines critical performance factors in BES, including inoculum selection, pretreatment methods, electrodes, and operational conditions. Further, authors explore innovative approaches to suppress methanogens and simultaneously enhance the EAM in mixed cultures. Additionally, advanced techniques for detecting EAM are discussed. The rapid detection of EAM facilitates the selection of suitable inoculum sources and optimization of enrichment strategies in BESs. This optimization is essential for facilitating the successful scaling up of BES applications, contributing substantially to the realization of clean energy and sustainable wastewater treatment. This analysis introduces a novel viewpoint by amalgamating contemporary research on the selective enrichment of EAM in mixed cultures. It encompasses identification and detection techniques, along with methodologies tailored for the selective enrichment of EAM, geared explicitly toward upscaling applications in BES.
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Affiliation(s)
- Ha T T Nguyen
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Department of Convergence Study on the Ocean Science and Technology, Ocean Science and Technology School (OST), Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Giang T H Le
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Sung-Gwan Park
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Dipak A Jadhav
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Trang T Q Le
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Hyunsu Kim
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Vandana Vinayak
- Diatom Nanoengineering and Metabolism Laboratory (DNM), School of Applied Science, Dr. Hari Singh Gour Central University, Sagar, MP 470003, India
| | - Gihan Lee
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Keunje Yoo
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea
| | - Young-Chae Song
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea.
| | - Kyu-Jung Chae
- Department of Environmental Engineering, College of Ocean Science and Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea; Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan 49112, Republic of Korea.
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2
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Wang N, Gao M, Liu S, Zhu W, Zhang Y, Wang X, Sun H, Guo Y, Wang Q. Electrochemical promotion of organic waste fermentation: Research advances and prospects. ENVIRONMENTAL RESEARCH 2024; 244:117422. [PMID: 37866529 DOI: 10.1016/j.envres.2023.117422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/24/2023]
Abstract
The current methods of treating organic waste suffer from limited resource usage and low product value. Research and development of value-added products emerges as an unavoidable trend for future growth. Electro-fermentation (EF) is a technique employed to stimulate cell proliferation, expedite microbial metabolism, and enhance the production of value-added products by administering minute voltages or currents in the fermentation system. This method represents a novel research direction lying at the crossroads of electrochemistry and biology. This article documents the current progress of EF for a range of value-added products, including gaseous fuels, organic acids, and other organics. It also presents novel value-added products, such as 1,3-propanediol, 3-hydroxypropionic acid, succinic acid, acrylic acid, and lysine. The latest research trends suggest a focus on EF for cogeneration of value-added products, studying microbial community structure and electroactive bacteria, exploring electron transfer mechanisms in EF systems, developing effective methods for nutrient recovery of nitrogen and phosphorus, optimizing EF conditions, and utilizing biosensors and artificial neural networks in this area. In this paper, an analysis is conducted on the challenges that currently exist regarding the selection of conductive materials, optimization of electrode materials, and development of bioelectrochemical system (BES) coupling processes in EF systems. The aim is to provide a reference for the development of more efficient, advanced, and value-added EF technologies. Overall, this paper aims to provide references and ideas for the development of more efficient and advanced EF technology.
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Affiliation(s)
- Nuohan Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Ming Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Shuo Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wenbin Zhu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuanchun Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xiaona Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Haishu Sun
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yan Guo
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Qunhui Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Tianjin College, University of Science and Technology Beijing, Tianjin, 301811, China.
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3
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Liu YN, Lv ZT, Lv WL, Liu DF, Liu XW. Label-Free Optical Imaging of the Electron Transfer in Single Live Microbial Cells. NANO LETTERS 2023; 23:558-566. [PMID: 36594792 DOI: 10.1021/acs.nanolett.2c04018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Measurement of electron transfer at the single-particle or -cell level is crucial to the in situ study of basic chemical and biological processes. However, it remains challenging to directly probe the microbial extracellular electron transfer process due to the weakness of signals and the lack of techniques. Here, we present a label-free and noninvasive imaging method that is able to measure the electron transfer in microbial cells. We measured the extracellular electron transfer processes by imaging the redox reaction of c-type outer membrane cytochromes in microbial cells using a plasmonic imaging technique, and obtained the electrochemical activity parameters (formal potential and number of electrons transferred) of multiple individual microbial cells, allowing for unveiling ample heterogeneities in electron transfer at the single-cell level. We anticipate that this method will contribute to the study of electron transfer in various biological and chemical processes.
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Affiliation(s)
- Yi-Nan Liu
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei230026, China
| | - Zhen-Ting Lv
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei230026, China
| | - Wen-Li Lv
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei230026, China
| | - Dong-Feng Liu
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei230026, China
| | - Xian-Wei Liu
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei230026, China
- Department of Applied Chemistry, University of Science and Technology of China, Hefei230026, China
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4
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Pereira J, de Nooy S, Sleutels T, Ter Heijne A. Opportunities for visual techniques to determine characteristics and limitations of electro-active biofilms. Biotechnol Adv 2022; 60:108011. [PMID: 35753624 DOI: 10.1016/j.biotechadv.2022.108011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/10/2022] [Accepted: 06/18/2022] [Indexed: 11/02/2022]
Abstract
Optimization of bio-electrochemical systems (BESs) relies on a better understanding of electro-active biofilms (EABfs). These microbial communities are studied with a range of techniques, including electrochemical, visual and chemical techniques. Even though each of these techniques provides very valuable and wide-ranging information about EABfs, such as performance, morphology and biofilm composition, they are often destructive. Therefore, the information obtained from EABfs development and characterization studies are limited to a single characterization of EABfs and often limited to one time point that determines the end of the experiment. Despite being scarcer and not as commonly reported as destructive techniques, non-destructive visual techniques can be used to supplement EABfs characterization by adding in-situ information of EABfs functioning and its development throughout time. This opens the door to EABfs monitoring studies that can complement the information obtained with destructive techniques. In this review, we provide an overview of visual techniques and discuss the opportunities for combination with the established electrochemical techniques to study EABfs. By providing an overview of suitable visual techniques and discussing practical examples of combination of visual with electrochemical methods, this review aims at serving as a source of inspiration for future studies in the field of BESs.
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Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Sam de Nooy
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
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5
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Sundaresan V, Do H, Shrout JD, Bohn PW. Electrochemical and spectroelectrochemical characterization of bacteria and bacterial systems. Analyst 2021; 147:22-34. [PMID: 34874024 PMCID: PMC8791413 DOI: 10.1039/d1an01954f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Microbes, such as bacteria, can be described, at one level, as small, self-sustaining chemical factories. Based on the species, strain, and even the environment, bacteria can be useful, neutral or pathogenic to human life, so it is increasingly important that we be able to characterize them at the molecular level with chemical specificity and spatial and temporal resolution in order to understand their behavior. Bacterial metabolism involves a large number of internal and external electron transfer processes, so it is logical that electrochemical techniques have been employed to investigate these bacterial metabolites. In this mini-review, we focus on electrochemical and spectroelectrochemical methods that have been developed and used specifically to chemically characterize bacteria and their behavior. First, we discuss the latest mechanistic insights and current understanding of microbial electron transfer, including both direct and mediated electron transfer. Second, we summarize progress on approaches to spatiotemporal characterization of secreted factors, including both metabolites and signaling molecules, which can be used to discern how natural or external factors can alter metabolic states of bacterial cells and change either their individual or collective behavior. Finally, we address in situ methods of single-cell characterization, which can uncover how heterogeneity in cell behavior is reflected in the behavior and properties of collections of bacteria, e.g. bacterial communities. Recent advances in (spectro)electrochemical characterization of bacteria have yielded important new insights both at the ensemble and the single-entity levels, which are furthering our understanding of bacterial behavior. These insights, in turn, promise to benefit applications ranging from biosensors to the use of bacteria in bacteria-based bioenergy generation and storage.
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Affiliation(s)
- Vignesh Sundaresan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Hyein Do
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Joshua D Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Paul W Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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6
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Smit SM, Buisman CJN, Bitter JH, Strik DPBTB. Cyclic Voltammetry is Invasive on Microbial Electrosynthesis. ChemElectroChem 2021. [DOI: 10.1002/celc.202100914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sanne M. Smit
- Environmental Technology Wageningen University and Research Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
- Biobased Chemistry and Technology Wageningen University and Research Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Cees J. N. Buisman
- Environmental Technology Wageningen University and Research Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - Johannes H. Bitter
- Biobased Chemistry and Technology Wageningen University and Research Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
| | - David P. B. T. B. Strik
- Environmental Technology Wageningen University and Research Axis-Z Bornse Weilanden 9 6708 WG Wageningen The Netherlands
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7
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Virdis B, Millo D, Donose BC, Lu Y, Batstone DJ, Krömer JO. Analysis of electron transfer dynamics in mixed community electroactive microbial biofilms. RSC Adv 2016. [DOI: 10.1039/c5ra15676a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrochemically active microbial biofilms are capable to produce electric current when grown onto electrodes. This work investigates the dynamics of electron transfer inside the biofilm as well as at the biofilm/electrode interface.
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Affiliation(s)
- Bernardino Virdis
- The University of Queensland
- Centre for Microbial Electrochemical Systems (CEMES)
- Brisbane
- Australia
- The University of Queensland
| | - Diego Millo
- Biomolecular Spectroscopy/LaserLaB Amsterdam
- Vrije Universiteit Amsterdam
- NL-1081 HV Amsterdam
- The Netherlands
| | - Bogdan C. Donose
- The University of Queensland
- Centre for Microbial Electrochemical Systems (CEMES)
- Brisbane
- Australia
- The University of Queensland
| | - Yang Lu
- The University of Queensland
- Advanced Water Management Centre (AWMC)
- Brisbane
- Australia
| | - Damien J. Batstone
- The University of Queensland
- Advanced Water Management Centre (AWMC)
- Brisbane
- Australia
| | - Jens O. Krömer
- The University of Queensland
- Centre for Microbial Electrochemical Systems (CEMES)
- Brisbane
- Australia
- The University of Queensland
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8
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Alves A, Ly HK, Hildebrandt P, Louro RO, Millo D. Nature of the Surface-Exposed Cytochrome-Electrode Interactions in Electroactive Biofilms of Desulfuromonas acetoxidans. J Phys Chem B 2015; 119:7968-74. [PMID: 26039558 DOI: 10.1021/acs.jpcb.5b03419] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Metal-respiring bacteria are microorganisms capable of oxidizing organic pollutants present in wastewater and transferring the liberated electrons to an electrode. This ability has led to their application as catalysts in bioelectrochemical systems (BESs), a sustainable technology coupling bioremediation to electricity production. Crucial for the functioning of these BESs is a complex protein architecture consisting of several surface-exposed multiheme proteins, called outer membrane cytochromes, wiring the cell metabolism to the electrode. Although the role of these proteins has been increasingly understood, little is known about the protein-electrode interactions and their impact on the performance of BESs. In this study, we used surface-enhanced resonance Raman spectroscopy in combination with electrochemical techniques to unravel the nature of the protein-electrode interaction for the outer membrane cytochrome OmcB from Desulfuromonas acetoxidans (Dace). Comparing the spectroelectrochemical properties of OmcB bound directly to the electrode surface with those of the same protein embedded inside an electroactive biofilm, we have shown that the surface-exposed cytochromes of Dace biofilms are in direct contact with the electrode surface. Even if direct binding causes protein denaturation, the biofilm possesses the ability to minimize the extent of the damage maximizing the amount of cells in direct electrical communication with the electrode.
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Affiliation(s)
- A Alves
- †Instituto de Tecnologia Quı́mica e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República-Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - H K Ly
- ‡Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - P Hildebrandt
- ‡Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - R O Louro
- †Instituto de Tecnologia Quı́mica e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República-Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - D Millo
- §Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Beese-Vasbender PF, Nayak S, Erbe A, Stratmann M, Mayrhofer KJ. Electrochemical characterization of direct electron uptake in electrical microbially influenced corrosion of iron by the lithoautotrophic SRB Desulfopila corrodens strain IS4. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.03.184] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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10
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Millo D, Ly HK. Towards the understanding of the effect of oxygen on the electrocatalytic activity of microbial biofilms: a spectroelectrochemical study. RSC Adv 2015. [DOI: 10.1039/c5ra17429e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metal-respiring bacteria oxidize an organic substrate and transfer the liberated electrons to the electrode. Molecular oxygen interrupts the current flow by cutting the electrical circuit wiring the cell metabolism to the electrode.
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Affiliation(s)
- D. Millo
- Department of Physics and Astronomy
- VU University Amsterdam
- 1081 HV Amsterdam
- The Netherlands
| | - H. K. Ly
- Technische Universität Berlin
- Institut für Chemie
- Germany
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11
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Virdis B, Millo D, Donose BC, Batstone DJ. Real-time measurements of the redox states of c-type cytochromes in electroactive biofilms: a confocal resonance Raman Microscopy study. PLoS One 2014; 9:e89918. [PMID: 24587123 PMCID: PMC3934938 DOI: 10.1371/journal.pone.0089918] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/28/2014] [Indexed: 11/19/2022] Open
Abstract
Confocal Resonance Raman Microscopy (CRRM) was used to probe variations of redox state of c-type cytochromes embedded in living mixed-culture electroactive biofilms exposed to different electrode polarizations, under potentiostatic and potentiodynamic conditions. In the absence of the metabolic substrate acetate, the redox state of cytochromes followed the application of reducing and oxidizing electrode potentials. Real-time monitoring of the redox state of cytochromes during cyclic voltammetry (CV) in a potential window where cytochromes reduction occurs, evidenced a measurable time delay between the oxidation of redox cofactors probed by CV at the electrode interface, and oxidation of distal cytochromes probed by CRRM. This delay was used to tentatively estimate the diffusivity of electrons through the biofilm. In the presence of acetate, the resonance Raman spectra of young (10 days, j = 208±49 µA cm−2) and mature (57 days, j = 267±73 µA cm−2) biofilms show that cytochromes remained oxidized homogeneously even at layers as far as 70 µm from the electrode, implying the existence of slow metabolic kinetics that do not result in the formation of a redox gradient inside the biofilm during anode respiration. However, old biofilms (80 days, j = 190±37 µA cm−2) with thickness above 100 µm were characterized by reduced catalytic activity compared to the previous developing stages. The cytochromes in these biofilm were mainly in the reduced redox state, showing that only aged mixed-culture biofilms accumulate electrons during anode respiration. These results differ substantially from recent observations in pure Geobacter sulfurreducens electroactive biofilms, in which accumulation of reduced cytochromes is already observed in thinner biofilms, thus suggesting different bottlenecks in current production for mixed-culture and G. sulfurreducens biofilms.
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Affiliation(s)
- Bernardino Virdis
- Centre for Microbial Electrosynthesis (CEMES), The University of Queensland, Brisbane, Queensland, Australia
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
| | - Diego Millo
- Biomolecular Spectroscopy/LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Bogdan C. Donose
- Centre for Microbial Electrosynthesis (CEMES), The University of Queensland, Brisbane, Queensland, Australia
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Queensland, Australia
| | - Damien J. Batstone
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Queensland, Australia
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12
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Lebedev N, Strycharz-Glaven SM, Tender LM. Spatially resolved confocal resonant Raman microscopic analysis of anode-grown Geobacter sulfurreducens biofilms. Chemphyschem 2014; 15:320-7. [PMID: 24402861 DOI: 10.1002/cphc.201300984] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Indexed: 11/09/2022]
Abstract
When grown on the surface of an anode electrode, Geobacter sulfurreducens forms a multi-cell thick biofilm in which all cells appear to couple the oxidation of acetate with electron transport to the anode, which serves as the terminal metabolic electron acceptor. Just how electrons are transported through such a biofilm from cells to the underlying anode surface over distances that can exceed 20 microns remains unresolved. Current evidence suggests it may occur by electron hopping through a proposed network of redox cofactors composed of immobile outer membrane and/or extracellular multi-heme c-type cytochromes. In the present work, we perform a spatially resolved confocal resonant Raman (CRR) microscopic analysis to investigate anode-grown Geobacter biofilms. The results confirm the presence of an intra-biofilm redox gradient whereby the probability that a heme is in the reduced state increases with increasing distance from the anode surface. Such a gradient is required to drive electron transport toward the anode surface by electron hopping via cytochromes. The results also indicate that at open circuit, when electrons are expected to accumulate in redox cofactors involved in electron transport due to the inability of the anode to accept electrons, nearly all c-type cytochrome hemes detected in the biofilm are oxidized. The same outcome occurs when a comparable potential to that measured at open circuit (-0.30 V vs. SHE) is applied to the anode, whereas nearly all hemes are reduced when an exceedingly negative potential (-0.50 V vs. SHE) is applied to the anode. These results suggest that nearly all c-type cytochrome hemes detected in the biofilm can be electrochemically accessed by the electrode, but most have oxidation potentials too negative to transport electrons originating from acetate metabolism. The results also reveal a lateral heterogeneity (x-y dimensions) in the type of c-type cytochromes within the biofilm that may affect electron transport to the electrode.
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Affiliation(s)
- Nikolai Lebedev
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC 20375 (USA).
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13
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Rimboud M, Pocaznoi D, Erable B, Bergel A. Electroanalysis of microbial anodes for bioelectrochemical systems: basics, progress and perspectives. Phys Chem Chem Phys 2014; 16:16349-66. [DOI: 10.1039/c4cp01698j] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over about the last ten years, microbial anodes have been the subject of a huge number of fundamental studies dealing with an increasing variety of possible application domains.
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Affiliation(s)
- M. Rimboud
- Laboratoire de Génie Chimique
- CNRS - Université de Toulouse
- 31432 Toulouse, France
| | - D. Pocaznoi
- Laboratoire de Génie Chimique
- CNRS - Université de Toulouse
- 31432 Toulouse, France
| | - B. Erable
- Laboratoire de Génie Chimique
- CNRS - Université de Toulouse
- 31432 Toulouse, France
| | - A. Bergel
- Laboratoire de Génie Chimique
- CNRS - Université de Toulouse
- 31432 Toulouse, France
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Li WJ, Kong SZ, Luo H, Jia ZB, Cheng Y. Electrochemical and spectroelectrochemical studies of four tanshinones from Salvia miltiorrhiza Bunge. CHINESE CHEM LETT 2013. [DOI: 10.1016/j.cclet.2013.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Electron transport at the microbe-mineral interface: a synthesis of current research challenges. Biochem Soc Trans 2013; 40:1163-6. [PMID: 23176448 DOI: 10.1042/bst20120242] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Many bacterial and archaeal species can couple growth to the respiratory reduction or oxidation of insoluble mineral oxides of transition metals. These solid substrates are abundant electron sinks and sources for life on Earth, but, since they are insoluble in water, they cannot enter the bacterial cells. So, to exploit these electron sinks and sources, specific respiratory electron-transfer mechanisms must overcome the physical limitations associated with electron transfer between a microbe and extracellular metal oxides. Recent microbiological, geochemical, biochemical, spectroscopic and structural work is beginning to shed light on the molecular mechanism and impacts of electron transfer at the microbe-mineral interface from a nanometre to kilometre scale. The research field is attracting attention in applied quarters from those with interests in nanowires, microbial fuel cells, bioremediation and microbial cell factories.
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Ly HK, Harnisch F, Hong SF, Schröder U, Hildebrandt P, Millo D. Unraveling the interfacial electron transfer dynamics of electroactive microbial biofilms using surface-enhanced Raman spectroscopy. CHEMSUSCHEM 2013; 6:487-492. [PMID: 23371822 DOI: 10.1002/cssc.201200626] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/05/2012] [Indexed: 06/01/2023]
Abstract
The electron transfer (ET) processes of electroactive microbial biofilms have been investigated by combining electrochemistry and time-resolved surface-enhanced resonance Raman (TR-SERR) spectroscopy. This experimental approach provides selective information on the ET process across the biofilm-electrode interface by monitoring the redox-state changes of heme cofactors in outer membrane cytochromes (OMCs) that are in close vicinity (i.e., within 7 nm) to the Ag working electrode. The rate constant for heterogeneous ET of the surface-confined OMCs (sc-OMCs) of a mixed culture derived electroactive microbial biofilm has been determined to be 0.03 s(-1) . In contrast, according to kinetic simulations the ET between sc-OMCs and their redox partners, embedded within the biofilm, is a much faster process with an estimated rate constant greater than 1.2 s(-1) . The slow rate of heterogeneous ET and the lack of high-spin species in the SERR spectra rule out the direct attachment of the sc-OMCs to the electrode surface.
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Affiliation(s)
- Hoang K Ly
- Institut für Chemie, Sekr. PC14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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