51
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Long-distance electron transfer in a filamentous Gram-positive bacterium. Nat Commun 2021; 12:1709. [PMID: 33731718 PMCID: PMC7969598 DOI: 10.1038/s41467-021-21709-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/05/2021] [Indexed: 01/31/2023] Open
Abstract
Long-distance extracellular electron transfer has been observed in Gram-negative bacteria and plays roles in both natural and engineering processes. The electron transfer can be mediated by conductive protein appendages (in short unicellular bacteria such as Geobacter species) or by conductive cell envelopes (in filamentous multicellular cable bacteria). Here we show that Lysinibacillus varians GY32, a filamentous unicellular Gram-positive bacterium, is capable of bidirectional extracellular electron transfer. In microbial fuel cells, L. varians can form centimetre-range conductive cellular networks and, when grown on graphite electrodes, the cells can reach a remarkable length of 1.08 mm. Atomic force microscopy and microelectrode analyses suggest that the conductivity is linked to pili-like protein appendages. Our results show that long-distance electron transfer is not limited to Gram-negative bacteria.
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52
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Vassilev I, Averesch NJH, Ledezma P, Kokko M. Anodic electro-fermentation: Empowering anaerobic production processes via anodic respiration. Biotechnol Adv 2021; 48:107728. [PMID: 33705913 DOI: 10.1016/j.biotechadv.2021.107728] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/31/2021] [Accepted: 03/03/2021] [Indexed: 11/24/2022]
Abstract
In nature as well as in industrial microbiology, all microorganisms need to achieve redox balance. Their redox state and energy conservation highly depend on the availability of a terminal electron acceptor, for example oxygen in aerobic production processes. Under anaerobic conditions in the absence of an electron acceptor, redox balance is achieved via the production of reduced carbon-compounds (fermentation). An alternative strategy to artificially stabilize microbial redox and energy state is the use of anodic electro-fermentation (AEF). This emerging biotechnology empowers respiration under anaerobic conditions using the anode of a bioelectrochemical system as an undepletable terminal electron acceptor. Electrochemical control of redox metabolism and energy conservation via AEF can steer the carbon metabolism towards a product of interest and avoid the need for continuous and cost-inefficient supply of oxygen as well as the production of mixed reduced by-products, as is the case in aerobic production and fermentation processes, respectively. The great challenge for AEF is to establish efficient extracellular electron transfer (EET) from the microbe to the anode and link it to central carbon metabolism to enhance the synthesis of a target product. This article reviews the advantages and challenges of AEF, EET mechanisms, microbial energy gain, and discusses the rational choice of substrate-product couple as well as the choice of microbial catalyst. Besides, it discusses the potential of the industrial model-organism Bacillus subtilis as a promising candidate for AEF, which has not been yet considered for such an application. This prospective review contributes to a better understanding of how industrial microbiology can benefit from AEF and analyses key-factors required to successfully implement AEF processes. Overall, this work aims to advance the young research field especially by critically revisiting the fundamental aspects of AEF.
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Affiliation(s)
- Igor Vassilev
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
| | - Nils J H Averesch
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States.
| | - Pablo Ledezma
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia.
| | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
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53
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Zhang X, Wang H, Xia T, Wang X. Characterization of a new electrochemically active bacterium phylogenetically related to Alicyclobacillus hesperidum and its electrochemical performance in microbial fuel cell. Biosens Bioelectron 2021; 175:112865. [PMID: 33277147 DOI: 10.1016/j.bios.2020.112865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 11/28/2022]
Abstract
Extremophilic microorganisms in microbial electrochemical systems have opened new possibilities for waste treatment. Here, a phenomenon of electricity generation under acidophilic condition was found in organic acid fermentation wastewater treatment using microbial fuel cell (MFC). The anodic microbial community analysis showed that the percentage of Firmicutes was 99.03%, which accounted for the vast majority of the microbial community at the late discharge stage with pH 3.0. As the dominant bacterium of Firmicutes, Alicyclobacillus hesperidum EG was isolated and identified. MFC experiments confirmed that Alicyclobacillus hesperidum EG exhibited good electricity generating capability with a maximum power density of 188.1 mW m-2 at 50 °C and low pH. It is the first time that Alicyclobacillus hesperidum EG was discovered as a newly electrochemically active bacterium. Additionally, the morphological analysis combined with electrochemical experiments demonstrated that no nanowires were found in the anodic biofilm of Alicyclobacillus hesperidum EG, and Alicyclobacillus hesperidum EG may produce soluble redox-active small molecules as electron shuttles to facilitate extracellular electron transfer. Based on unique characteristics such as good acid resistance, high temperature resistance, and high electricity generation ability, Alicyclobacillus hesperidum EG exhibited great potential in wastewater treatment and energy recovery.
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Affiliation(s)
- Xueli Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Huimin Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Tian Xia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China.
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54
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Ramanavicius S, Ramanavicius A. Charge Transfer and Biocompatibility Aspects in Conducting Polymer-Based Enzymatic Biosensors and Biofuel Cells. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:371. [PMID: 33540587 PMCID: PMC7912793 DOI: 10.3390/nano11020371] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/23/2021] [Accepted: 01/24/2021] [Indexed: 02/06/2023]
Abstract
Charge transfer (CT) is a very important issue in the design of biosensors and biofuel cells. Some nanomaterials can be applied to facilitate the CT in these bioelectronics-based devices. In this review, we overview some CT mechanisms and/or pathways that are the most frequently established between redox enzymes and electrodes. Facilitation of indirect CT by the application of some nanomaterials is frequently applied in electrochemical enzymatic biosensors and biofuel cells. More sophisticated and still rather rarely observed is direct charge transfer (DCT), which is often addressed as direct electron transfer (DET), therefore, DCT/DET is also targeted and discussed in this review. The application of conducting polymers (CPs) for the immobilization of enzymes and facilitation of charge transfer during the design of biosensors and biofuel cells are overviewed. Significant attention is paid to various ways of synthesis and application of conducting polymers such as polyaniline, polypyrrole, polythiophene poly(3,4-ethylenedioxythiophene). Some DCT/DET mechanisms in CP-based sensors and biosensors are discussed, taking into account that not only charge transfer via electrons, but also charge transfer via holes can play a crucial role in the design of bioelectronics-based devices. Biocompatibility aspects of CPs, which provides important advantages essential for implantable bioelectronics, are discussed.
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Affiliation(s)
- Simonas Ramanavicius
- Department of Physical Chemistry, Faculty of Chemistry and Geosciences, Institute of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
| | - Arunas Ramanavicius
- Department of Physical Chemistry, Faculty of Chemistry and Geosciences, Institute of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
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55
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Faustino MM, Fonseca BM, Costa NL, Lousa D, Louro RO, Paquete CM. Crossing the Wall: Characterization of the Multiheme Cytochromes Involved in the Extracellular Electron Transfer Pathway of Thermincola ferriacetica. Microorganisms 2021; 9:microorganisms9020293. [PMID: 33572691 PMCID: PMC7911101 DOI: 10.3390/microorganisms9020293] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
Bioelectrochemical systems (BES) are emerging as a suite of versatile sustainable technologies to produce electricity and added-value compounds from renewable and carbon-neutral sources using electroactive organisms. The incomplete knowledge on the molecular processes that allow electroactive organisms to exchange electrons with electrodes has prevented their real-world implementation. In this manuscript we investigate the extracellular electron transfer processes performed by the thermophilic Gram-positive bacteria belonging to the Thermincola genus, which were found to produce higher levels of current and tolerate higher temperatures in BES than mesophilic Gram-negative bacteria. In our study, three multiheme c-type cytochromes, Tfer_0070, Tfer_0075, and Tfer_1887, proposed to be involved in the extracellular electron transfer pathway of T. ferriacetica, were cloned and over-expressed in E. coli. Tfer_0070 (ImdcA) and Tfer_1887 (PdcA) were purified and biochemically characterized. The electrochemical characterization of these proteins supports a pathway of extracellular electron transfer via these two proteins. By contrast, Tfer_0075 (CwcA) could not be stabilized in solution, in agreement with its proposed insertion in the peptidoglycan wall. However, based on the homology with the outer-membrane cytochrome OmcS, a structural model for CwcA was developed, providing a molecular perspective into the mechanisms of electron transfer across the peptidoglycan layer in Thermincola.
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56
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Gavrilov SN, Zavarzina DG, Elizarov IM, Tikhonova TV, Dergousova NI, Popov VO, Lloyd JR, Knight D, El-Naggar MY, Pirbadian S, Leung KM, Robb FT, Zakhartsev MV, Bretschger O, Bonch-Osmolovskaya EA. Novel Extracellular Electron Transfer Channels in a Gram-Positive Thermophilic Bacterium. Front Microbiol 2021; 11:597818. [PMID: 33505370 PMCID: PMC7829351 DOI: 10.3389/fmicb.2020.597818] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 12/04/2020] [Indexed: 12/22/2022] Open
Abstract
Biogenic transformation of Fe minerals, associated with extracellular electron transfer (EET), allows microorganisms to exploit high-potential refractory electron acceptors for energy generation. EET-capable thermophiles are dominated by hyperthermophilic archaea and Gram-positive bacteria. Information on their EET pathways is sparse. Here, we describe EET channels in the thermophilic Gram-positive bacterium Carboxydothermus ferrireducens that drive exoelectrogenesis and rapid conversion of amorphous mineral ferrihydrite to large magnetite crystals. Microscopic studies indicated biocontrolled formation of unusual formicary-like ultrastructure of the magnetite crystals and revealed active colonization of anodes in bioelectrochemical systems (BESs) by C. ferrireducens. The internal structure of micron-scale biogenic magnetite crystals is reported for the first time. Genome analysis and expression profiling revealed three constitutive c-type multiheme cytochromes involved in electron exchange with ferrihydrite or an anode, sharing insignificant homology with previously described EET-related cytochromes thus representing novel determinants of EET. Our studies identify these cytochromes as extracellular and reveal potentially novel mechanisms of cell-to-mineral interactions in thermal environments.
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Affiliation(s)
- Sergey N Gavrilov
- Winogradsky Institute of Microbiology, FRC Biotechnology Russian Academy of Sciences, Moscow, Russia
| | - Daria G Zavarzina
- Winogradsky Institute of Microbiology, FRC Biotechnology Russian Academy of Sciences, Moscow, Russia
| | - Ivan M Elizarov
- Winogradsky Institute of Microbiology, FRC Biotechnology Russian Academy of Sciences, Moscow, Russia
| | - Tamara V Tikhonova
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Natalia I Dergousova
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir O Popov
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia.,Kurchatov Complex NBICS-Technologies, National Research Center "Kurchatov Institute," Moscow, Russia
| | - Jonathan R Lloyd
- Dalton Nuclear Institute, FSE Research Institutes, The University of Manchester, Manchester, United Kingdom
| | - David Knight
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | | | - Sahand Pirbadian
- University of Southern California, Los Angeles, CA, United States
| | - Kar Man Leung
- University of Southern California, Los Angeles, CA, United States
| | - Frank T Robb
- School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | | | | | - Elizaveta A Bonch-Osmolovskaya
- Winogradsky Institute of Microbiology, FRC Biotechnology Russian Academy of Sciences, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
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57
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Ferrer-Vilanova A, Alonso Y, Dietvorst J, Pérez-Montero M, Rodríguez-Rodríguez R, Ivanova K, Tzanov T, Vigués N, Mas J, Guirado G, Muñoz-Berbel X. Sonochemical coating of Prussian Blue for the production of smart bacterial-sensing hospital textiles. ULTRASONICS SONOCHEMISTRY 2021; 70:105317. [PMID: 32891882 PMCID: PMC7786536 DOI: 10.1016/j.ultsonch.2020.105317] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/02/2020] [Accepted: 08/23/2020] [Indexed: 05/22/2023]
Abstract
In healthcare facilities, environmental microbes are responsible for numerous infections leading to patient's health complications and even death. The detection of the pathogens present on contaminated surfaces is crucial, although not always possible with current microbial detection technologies requiring sample collection and transfer to the laboratory. Based on a simple sonochemical coating process, smart hospital fabrics with the capacity to detect live bacteria by a simple change of colour are presented here. Prussian Blue nanoparticles (PB-NPs) are sonochemically coated on polyester-cotton textiles in a single-step requiring 15 min. The presence of PB-NPs confers the textile with an intensive blue colour and with bacterial-sensing capacity. Live bacteria in the textile metabolize PB-NPs and reduce them to colourless Prussian White (PW), enabling in situ detection of bacterial presence in less than 6 h with the bare eye (complete colour change requires 40 h). The smart textile is sensitive to both Gram-positive and Gram-negative bacteria, responsible for most nosocomial infections. The redox reaction is completely reversible and the textile recovers its initial blue colour by re-oxidation with environmental oxygen, enabling its re-use. Due to its simplicity and versatility, the current technology can be employed in different types of materials for control and prevention of microbial infections in hospitals, industries, schools and at home.
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Affiliation(s)
- Amparo Ferrer-Vilanova
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Carrer dels Til·lers s/n, Campus Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Yasmine Alonso
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Jiri Dietvorst
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Carrer dels Til·lers s/n, Campus Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Marta Pérez-Montero
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, 08195, Sant Cugat del Vallès, Barcelona, Spain.
| | - Rosalía Rodríguez-Rodríguez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, 08195, Sant Cugat del Vallès, Barcelona, Spain.
| | - Kristina Ivanova
- Universitat Politècnica de Catalunya, Edifici Gaia, Pg. Ernest Lluch/Rambla Sant Nebridi s/n. 08222, Terrassa, Barcelona, Spain.
| | - Tzanko Tzanov
- Universitat Politècnica de Catalunya, Edifici Gaia, Pg. Ernest Lluch/Rambla Sant Nebridi s/n. 08222, Terrassa, Barcelona, Spain.
| | - Núria Vigués
- Departament de Genètica i Microbiologia, Universitat Autonòma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Jordi Mas
- Departament de Genètica i Microbiologia, Universitat Autonòma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Gonzalo Guirado
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
| | - Xavier Muñoz-Berbel
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Carrer dels Til·lers s/n, Campus Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain.
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58
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Pham MT, Yang JJ, Balasubramaniam A, Rahim AR, Adi P, Do TTM, Herr DR, Huang CM. Leuconostoc mesenteroides mediates an electrogenic pathway to attenuate the accumulation of abdominal fat mass induced by high fat diet. Sci Rep 2020; 10:21916. [PMID: 33318546 PMCID: PMC7736347 DOI: 10.1038/s41598-020-78835-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/27/2020] [Indexed: 11/26/2022] Open
Abstract
Although several electrogenic bacteria have been identified, the physiological effect of electricity generated by bacteria on host health remains elusive. We found that probiotic Leuconostoc mesenteroides (L. mesenteroides) can metabolize linoleic acid to yield electricity via an intracellular cyclophilin A-dependent pathway. Inhibition of cyclophilin A significantly abolished bacterial electricity and lowered the adhesion of L. mesenteroides to the human gut epithelial cell line. Butyrate from L. mesenteroides in the presence of linoleic acid were detectable and mediated free fatty acid receptor 2 (Ffar2) to reduce the lipid contents in differentiating 3T3-L1 adipocytes. Oral administration of L. mesenteroides plus linoleic acid remarkably reduced high-fat-diet (HFD)-induced formation of 4-hydroxy-2-nonenal (4-HNE), a reactive oxygen species (ROS) biomarker, and decreased abdominal fat mass in mice. The reduction of 4-HNE and abdominal fat mass was reversed when cyclophilin A inhibitor-pretreated bacteria were administered to mice. Our studies present a novel mechanism of reducing abdominal fat mass by electrogenic L. mesenteroides which may yield electrons to enhance colonization and sustain high amounts of butyrate to limit ROS during adipocyte differentiation.
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Affiliation(s)
- Minh Tan Pham
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - John Jackson Yang
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Arun Balasubramaniam
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - Adelia Riezka Rahim
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - Prakoso Adi
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - Thi Tra My Do
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - Deron Raymond Herr
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
| | - Chun-Ming Huang
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, 32001, Taiwan.
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59
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Román LE, Gomez ED, Solís JL, Gómez MM. Antibacterial Cotton Fabric Functionalized with Copper Oxide Nanoparticles. Molecules 2020; 25:E5802. [PMID: 33316935 PMCID: PMC7764683 DOI: 10.3390/molecules25245802] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022] Open
Abstract
Textiles functionalized with cupric oxide (CuO) nanoparticles have become a promising option to prevent the spread of diseases due to their antimicrobial properties, which strongly depend on the structure and morphology of the nanoparticles and the method used for the functionalization process. This article presents a review of work focused on textiles functionalized with CuO nanoparticles, which were classified into two groups, namely, in situ and ex situ. Moreover, the analyzed bacterial strains, the resistance of the antimicrobial properties of textiles to washing processes, and their cytotoxicity were identified. Finally, the possible antimicrobial mechanisms that could develop in Gram-positive and Gram-negative bacteria were described.
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Affiliation(s)
- Luz E. Román
- Faculty of Science, Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Lima 15333, Peru; (L.E.R.); (J.L.S.)
| | - Enrique D. Gomez
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA;
- Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - José L. Solís
- Faculty of Science, Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Lima 15333, Peru; (L.E.R.); (J.L.S.)
| | - Mónica M. Gómez
- Faculty of Science, Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Lima 15333, Peru; (L.E.R.); (J.L.S.)
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60
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Xiao X, Yu HQ. Molecular mechanisms of microbial transmembrane electron transfer of electrochemically active bacteria. Curr Opin Chem Biol 2020; 59:104-110. [DOI: 10.1016/j.cbpa.2020.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 10/23/2022]
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61
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Paquete CM. Electroactivity across the cell wall of Gram-positive bacteria. Comput Struct Biotechnol J 2020; 18:3796-3802. [PMID: 33335679 PMCID: PMC7720022 DOI: 10.1016/j.csbj.2020.11.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
The growing interest on sustainable biotechnological processes for the production of energy and industrial relevant organic compounds have increased the discovery of electroactive organisms (i.e. organisms that are able to exchange electrons with an electrode) and the characterization of their extracellular electron transfer mechanisms. While most of the knowledge on extracellular electron transfer processes came from studies on Gram-negative bacteria, less is known about the processes performed by Gram-positive bacteria. In contrast to Gram-negative bacteria, Gram-positive bacteria lack an outer-membrane and contain a thick cell wall, which were thought to prevent extracellular electron transfer. However, in the last decade, an increased number of Gram-positive bacteria have been found to perform extracellular electron transfer, and exchange electrons with an electrode. In this mini-review the current knowledge on the extracellular electron transfer processes performed by Gram-positive bacteria is introduced, emphasising their electroactive role in bioelectrochemical systems. Also, the existent information of the molecular processes by which these bacteria exchange electrons with an electrode is highlighted. This understanding is fundamental to advance the implementation of these organisms in sustainable biotechnological processes, either through modification of the systems or through genetic engineering, where the organisms can be optimized to become better catalysts.
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Affiliation(s)
- Catarina M. Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Portugal
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62
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Tahernia M, Plotkin-Kaye E, Mohammadifar M, Gao Y, Oefelein MR, Cook LC, Choi S. Characterization of Electrogenic Gut Bacteria. ACS OMEGA 2020; 5:29439-29446. [PMID: 33225175 PMCID: PMC7676329 DOI: 10.1021/acsomega.0c04362] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/29/2020] [Indexed: 05/13/2023]
Abstract
While electrogenic, or electricity-producing, Gram-negative bacteria predominantly found in anaerobic habitats have been intensively explored, the potential of Gram-positive microbial electrogenic capability residing in a similar anoxic environment has not been considered. Because Gram-positive bacteria contain a thick non-conductive cell wall, they were previously believed to be very weak exoelectrogens. However, with the recent discovery of electrogenicity by Gram-positive pathogens and elucidation of their electron-transfer pathways, significant and accelerated attention has been given to the discovery and characterization of these pathways in the members of gut microbiota. The discovery of electrogenic bacteria present in the human gut and the understanding of their electrogenic capacity opens up possibilities of bacterial powered implantable batteries and provide a novel biosensing platform to monitor human gastrointestinal health. In this work, we characterized microbial extracellular electron-transfer capabilities and capacities of five gut bacteria: Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, Lactobacillus reuteri, and Lactobacillus rhamnosus. A 21-well paper-based microbial fuel cell array with enhanced sensitivity was developed as a powerful yet simple screening method to accurately and simultaneously characterize bacterial electrogenicity. S. aureus, E. faecalis, and S. agalactiae exhibited distinct electrogenic capabilities, and their power generations were comparable to that of the well-known Gram-negative exoelectrogen, Shewanella oneidensis. Importantly, this system was used to begin a large-scale transposon screen to examine the genes involved in electrogenicity by the human pathobiont S. aureus.
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Affiliation(s)
- Mehdi Tahernia
- Bioelectronics
& Microsystems Laboratory, Department of Electrical & Computer
Engineering, State University of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Ellie Plotkin-Kaye
- Department
of Biological Science, State University
of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Maedeh Mohammadifar
- Bioelectronics
& Microsystems Laboratory, Department of Electrical & Computer
Engineering, State University of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Yang Gao
- Bioelectronics
& Microsystems Laboratory, Department of Electrical & Computer
Engineering, State University of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Melissa R. Oefelein
- Department
of Biological Science, State University
of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Laura C. Cook
- Department
of Biological Science, State University
of New York-Binghamton, Binghamton, New York 13902-6000, United States
| | - Seokheun Choi
- Bioelectronics
& Microsystems Laboratory, Department of Electrical & Computer
Engineering, State University of New York-Binghamton, Binghamton, New York 13902-6000, United States
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63
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Chen H, Simoska O, Lim K, Grattieri M, Yuan M, Dong F, Lee YS, Beaver K, Weliwatte S, Gaffney EM, Minteer SD. Fundamentals, Applications, and Future Directions of Bioelectrocatalysis. Chem Rev 2020; 120:12903-12993. [DOI: 10.1021/acs.chemrev.0c00472] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hui Chen
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Olja Simoska
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Koun Lim
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Matteo Grattieri
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Mengwei Yuan
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Fangyuan Dong
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Yoo Seok Lee
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Kevin Beaver
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Samali Weliwatte
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Erin M. Gaffney
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Shelley D. Minteer
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
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64
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Shrestha N, Tripathi AK, Govil T, Sani RK, Urgun-Demirtas M, Kasthuri V, Gadhamshetty V. Electricity from lignocellulosic substrates by thermophilic Geobacillus species. Sci Rep 2020; 10:17047. [PMID: 33046790 PMCID: PMC7552438 DOI: 10.1038/s41598-020-72866-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/03/2020] [Indexed: 11/09/2022] Open
Abstract
Given our vast lignocellulosic biomass reserves and the difficulty in bioprocessing them without expensive pretreatment and fuel separation steps, the conversion of lignocellulosic biomass directly into electricity would be beneficial. Here we report the previously unexplored capabilities of thermophilic Geobacillus sp. strain WSUCF1 to generate electricity directly from such complex substrates in microbial fuel cells. This process obviates the need for exogenous enzymes and redox mediator supplements. Cyclic voltammetry and chromatography studies revealed the electrochemical signatures of riboflavin molecules that reflect mediated electron transfer capabilities of strain WSUCF1. Proteomics and genomics analysis corroborated that WSUCF1 biofilms uses type-II NADH dehydrogenase and demethylmenaquinone methyltransferase to transfer the electrons to conducting anode via the redox active pheromone lipoproteins localized at the cell membrane.
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Affiliation(s)
- Namita Shrestha
- Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA. .,Department of Civil and Environmental Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, 47803, USA.
| | - Abhilash Kumar Tripathi
- Department of Biological and Chemical Engineering, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA
| | - Tanvi Govil
- Department of Biological and Chemical Engineering, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA
| | - Rajesh Kumar Sani
- Department of Biological and Chemical Engineering, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA. .,BuGReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA.
| | - Meltem Urgun-Demirtas
- Energy Global Security Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Venkateswaran Kasthuri
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Venkataramana Gadhamshetty
- Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA. .,BuGReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA.
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65
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Tahernia M, Mohammadifar M, Liu L, Choi S. A Disposable, Papertronic Three-Electrode Potentiostat for Monitoring Bacterial Electrochemical Activity. ACS OMEGA 2020; 5:24717-24723. [PMID: 33015489 PMCID: PMC7528304 DOI: 10.1021/acsomega.0c03299] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/11/2020] [Indexed: 05/28/2023]
Abstract
Bacterial electrochemical activities can promote sustainable energy and environmental engineering applications. Characterizing their ability is critical for effectively adopting these technologies. Conventional studies of the electroactive bacteria are limited to insensitive, time-consuming, and labor-intensive two-electrode microbial fuel cell (MFC) techniques. Even the latest miniaturized MFC array is limited by irreproducibility and uncontrollability. In this work, we created a 4-well electrochemical sensing array with an integrated, custom-made three-electrode potentiostat to provide a controllable analytic capability without unwanted perturbations. A simple potentiostat circuit used two operational amplifiers and one resistor, allowing chronoamperometric and staircase voltammetric analyses of three well-known electroactive bacteria species: Shewanella oneidensis MR1, Pseudomonas aeruginosa PAO1, and Bacillus subtilis. Portability and disposability were emphasized by integrating all the functions into a paper substrate, which makes analyses possible at the point-of-use and in resource-limited settings without a bulky and expensive benchtop potentiostat. After use, the papertronic system was disposed of safely by incineration without posing any bacterial cytotoxic risks. This novel sensing platform creates an inexpensive, scalable, time-saving, high-performance, and user-friendly platform that facilitates the study of fundamental electrocatalytic activities of bacteria.
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66
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Methanogenesis inhibitors used in bio-electrochemical systems: A review revealing reality to decide future direction and applications. BIORESOURCE TECHNOLOGY 2020; 319:124141. [PMID: 32977094 DOI: 10.1016/j.biortech.2020.124141] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/11/2020] [Accepted: 09/13/2020] [Indexed: 02/08/2023]
Abstract
Microbial fuel cell (MFC) is a robust technology capable of treating real wastewaters by utilizing mixed anaerobic microbiota as inoculum for producing electricity from oxidation of the biodegradable matters. However, these mixed microbiota comprises of both electroactive microorganisms (EAM) and substrate/electron scavenging microorganisms such as methanogens. Hence, in order to maximize bioelectricity from MFC, different physio-chemical techniques have been applied in past investigations to suppress activity of methanogens. Interestingly, recent investigations exhibit that methanogens can produce electricity in MFC and possess the cellular machinery like cytochrome c and Type IV pili to perform extracellular electron transfer (EET) in the presence of suitable electron acceptors. Hence, in this review, in-depth analysis of versatile behaviour of methanogens in both MFC and natural anaerobic conditions with different inhibition techniques is explored. This review also discusses the future research directions based on the latest scientific evidence on role of methanogens for EET in MFC.
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67
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Gao Y, Ryu J, Liu L, Choi S. A simple, inexpensive, and rapid method to assess antibiotic effectiveness against exoelectrogenic bacteria. Biosens Bioelectron 2020; 168:112518. [PMID: 32862095 DOI: 10.1016/j.bios.2020.112518] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/07/2020] [Accepted: 08/13/2020] [Indexed: 01/05/2023]
Abstract
A sufficiently fast and simple antimicrobial susceptibility testing (AST) is urgently required to guide effective antibiotic usages and to surveil the antimicrobial resistance rate. Here, we establish a rapid, quantitative, and high-throughput phenotypic AST by measuring electrons transferred from the interiors of microbial cells to external electrodes. Because the transferred electrons are based on microbial metabolic activities and are inversely proportional to the concentration of potential antibiotics, the changes in electrical outputs can be readily used as a transducing signal to efficiently monitor bacterial growth and antibiotic susceptibility. The sensing is performed by directly measuring the total energy, or all the accumulated microbial electricity, generated by microbial fuel cells (MFCs) arranged in a large-capacity disposable, paper-based testbed. A common Gram-negative pathogenic bacterium Pseudomonas aeruginosa wild-type PAO1 and first-line antibiotic gentamicin (GEN) are used in our experiments. The minimum inhibitory concentration (MIC) values generated from our technique are validated by the gold standard broth microdilution (BMD). Our new approach provides quantitative, actionable MIC results within just 5 h because it measures electricity produced by bacterial metabolism instead of the days needed for growth-observation methods. Moreover, as the equipment needed is simple, common, and inexpensive, our test has immense potential to be adopted in the field or resource-limited hospitals and labs to provide insightful assessments for research and clinical practices.
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Affiliation(s)
- Yang Gao
- Bioelectronics & Microsystems Laboratory, Department of Electrical & Computer Engineering, State University of New York at Binghamton, 4400, Vestal Pkwy East, Binghamton, NY, USA
| | - Jihyun Ryu
- Bioelectronics & Microsystems Laboratory, Department of Electrical & Computer Engineering, State University of New York at Binghamton, 4400, Vestal Pkwy East, Binghamton, NY, USA
| | - Lin Liu
- Bioelectronics & Microsystems Laboratory, Department of Electrical & Computer Engineering, State University of New York at Binghamton, 4400, Vestal Pkwy East, Binghamton, NY, USA
| | - Seokheun Choi
- Bioelectronics & Microsystems Laboratory, Department of Electrical & Computer Engineering, State University of New York at Binghamton, 4400, Vestal Pkwy East, Binghamton, NY, USA.
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68
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Hubenova Y, Hubenova E, Mitov M. Electroactivity of the Gram-positive bacterium Paenibacillus dendritiformis MA-72. Bioelectrochemistry 2020; 136:107632. [PMID: 32795939 DOI: 10.1016/j.bioelechem.2020.107632] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 01/23/2023]
Abstract
Whilst most of the microorganisms recognized as exoelectrogens are Gram-negative bacteria, the electrogenicity of Gram-positive bacteria has not been sufficiently explored. In this study, the putative electroactivity of the Gram-positive Paenibacillus dendritiformis MA-72 strain, isolated from the anodic biofilm of long-term operated Sediment Microbial Fuel Cell (SMFC), has been investigated. SEM observations show that under polarization conditions P. dendritiformis forms a dense biofilm on carbon felt electrodes. A current density, reaching 5 mA m-2, has been obtained at a prolonged applied potential of -0.195 V (vs. SHE), which represents 35% of the value achieved with the SMFC. The voltammetric studies confirm that the observed Faradaic current is associated with the electrochemical activity of the bacterial biofilm and not with a soluble redox mediator. The results suggest that a direct electron transfer takes place through the conductive extracellular polymer matrix via pili/nanowires and multiple cytochromes. All these findings demonstrate for the first time that the Gram-positive Paenibacillus dendritiformis MA-72 is a new exoelectrogenic bacterial strain.
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Affiliation(s)
- Yolina Hubenova
- Department of Electrocatalysis and Electrocrystallization, Institute of Electrochemistry and Energy Systems "Acad. E. Budevski" - Bulgarian Academy of Sciences, Sofia, Bulgaria; Department of Biochemistry and Microbiology, Plovdiv University "Paisii Hilendarski", Plovdiv, Bulgaria.
| | - Eleonora Hubenova
- Medical Faculty of the Rhein Friedrich Wilhelm University of Bonn, Bonn, Germany
| | - Mario Mitov
- Innovative Center for Eco Energy Technologies, South-West University "Neofit Rilski", Blagoevgrad, Bulgaria
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69
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Liu DF, Li WW. Potential-dependent extracellular electron transfer pathways of exoelectrogens. Curr Opin Chem Biol 2020; 59:140-146. [PMID: 32769012 DOI: 10.1016/j.cbpa.2020.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 10/23/2022]
Abstract
Exoelectrogens are distinct from other bacteria owing to their unique extracellular electron transfer (EET) abilities that allow for anaerobic respiration with various external redox-active surfaces, including electrode and metal oxides. Although the EET process is known to trigger diverse extracellular redox reactions, the reverse impact has been long overlooked. Recent evidences show that exoelectrogens can sense the potential changes of external surfaces and alter their EET strategies accordingly, which imparts them remarkable abilities in adapting to diverse and redox-variable environment. This mini-review provides a condensed overview and critical analysis about the recent discoveries on redox-dependent EET pathways of exoelectrogens, with focus on Geobacter sulfurreducens and Shewanella oneidensis. We summarize the detailed responses of various EET components, analyze the drives and mechanisms of such responses, highlight the diversity of EET dynamics among different bacterial species and under integrated effects of redox potential and surface chemistry, and discusses the future research needs.
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Affiliation(s)
- Dong-Feng Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Wen-Wei Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China; USTC-City U Joint Advanced Research Center, Suzhou 215123, China.
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70
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Naradasu D, Miran W, Okamoto A. Metabolic Current Production by an Oral Biofilm Pathogen Corynebacterium matruchotii. Molecules 2020; 25:molecules25143141. [PMID: 32660074 PMCID: PMC7397247 DOI: 10.3390/molecules25143141] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/01/2020] [Accepted: 07/07/2020] [Indexed: 11/16/2022] Open
Abstract
The development of a simple and direct assay for quantifying microbial metabolic activity is important for identifying antibiotic drugs. Current production capabilities of environmental bacteria via the process called extracellular electron transport (EET) from the cell interior to the exterior is well investigated in mineral-reducing bacteria and have been used for various energy and environmental applications. Recently, the capability of human pathogens for producing current has been identified in different human niches, which was suggested to be applicable for drug assessment, because the current production of a few strains correlated with metabolic activity. Herein, we report another strain, a highly abundant pathogen in human oral polymicrobial biofilm, Corynebacterium matruchotii, to have the current production capability associated with its metabolic activity. It showed the current production of 50 nA/cm2 at OD600 of 0.1 with the working electrode poised at +0.4 V vs. a standard hydrogen electrode in a three-electrode system. The addition of antibiotics that suppress the microbial metabolic activity showed a significant current decrease (>90%), establishing that current production reflected the cellular activity in this pathogen. Further, the metabolic fixation of atomically labeled 13C (31.68% ± 2.26%) and 15N (19.69% ± 1.41%) confirmed by high-resolution mass spectrometry indicated that C. matruchotii cells were metabolically active on the electrode surface. The identified electrochemical activity of C. matruchotii shows that this can be a simple and effective test for evaluating the impact of antibacterial compounds, and such a method might be applicable to the polymicrobial oral biofilm on electrode surfaces, given four other oral pathogens have already been shown the current production capability.
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Affiliation(s)
- Divya Naradasu
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; (D.N.); (W.M.)
| | - Waheed Miran
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; (D.N.); (W.M.)
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; (D.N.); (W.M.)
- Center for Sensor and Actuator Material, 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
- Correspondence:
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71
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Cao M, Feng Y, Wang N, Li Y, Li N, Liu J, He W. Electrochemical regulation on the metabolism of anode biofilms under persistent exogenous bacteria interference. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.135922] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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72
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Exploration of Electrochemcially Active Bacterial Strains for Microbial Fuel Cells: An Innovation in Bioelectricity Generation. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.1.12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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73
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Two Routes for Extracellular Electron Transfer in Enterococcus faecalis. J Bacteriol 2020; 202:JB.00725-19. [PMID: 31932308 DOI: 10.1128/jb.00725-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 12/20/2019] [Indexed: 12/14/2022] Open
Abstract
Enterococcus faecalis cells are known to have ferric reductase activity and the ability to transfer electrons generated in metabolism to the external environment. We have isolated mutants defective in ferric reductase activity and studied their electron transfer properties to electrodes mediated by ferric ions and an osmium complex-modified redox polymer (OsRP). Electron transfer mediated with ferric ions and ferric reductase activity were both found to be dependent on the membrane-associated Ndh3 and EetA proteins, consistent with findings in Listeria monocytogenes In contrast, electron transfer mediated with OsRP was independent of these two proteins. Quinone in the cell membrane was required for the electron transfer with both mediators. The combined results demonstrate that extracellular electron transfer from reduced quinone to ferric ions and to OsRP occurs via different routes in the cell envelope of E. faecalis IMPORTANCE The transfer of reducing power in the form of electrons, generated in the catabolism of nutrients, from a bacterium to an extracellular acceptor appears to be common in nature. The electron acceptor can be another cell or abiotic material. Such extracellular electron transfer contributes to syntrophic metabolism and is of wide environmental, industrial, and medical importance. Electron transfer between microorganisms and electrodes is fundamental in microbial fuel cells for energy production and for electricity-driven synthesis of chemical compounds in cells. In contrast to the much-studied extracellular electron transfer mediated by cell surface exposed cytochromes, little is known about components and mechanisms for such electron transfer in organisms without these cytochromes and in Gram-positive bacteria such as E. faecalis, which is a commensal gut lactic acid bacterium and opportunistic pathogen.
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74
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Moscoviz R, Quéméner EDL, Trably E, Bernet N, Hamelin J. Novel Outlook in Microbial Ecology: Nonmutualistic Interspecies Electron Transfer. Trends Microbiol 2020; 28:245-253. [PMID: 32155432 DOI: 10.1016/j.tim.2020.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 02/06/2023]
Abstract
Recent advances in microbial electrochemical technologies have revealed the existence of numerous and highly diverse microorganisms able to exchange electrons with electrodes. This diversity could reflect the capacity of microorganisms to release and/or retrieve electrons with each other in natural environments. So far, this interspecies electron transfer has been studied with a special focus on syntrophy and was successfully demonstrated for several couples of species. In this article we argue that electron exchange between microbes exists beyond syntrophy or mutualism and could also promote competitive and even parasitic behaviour. Based on three interesting case studies identified from the literature, we also highlight that such nonmutualistic interactions could be widespread and of particular significance for the survival of pathogens or the shaping of complex microbial communities.
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Affiliation(s)
- Roman Moscoviz
- SUEZ, Centre International de Recherche Sur l'Eau et l'Environnement (CIRSEE), Le Pecq, France.
| | | | - Eric Trably
- INRAE, Université Montpellier, LBE, Narbonne, France
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75
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How does electron transfer occur in microbial fuel cells? World J Microbiol Biotechnol 2020; 36:19. [PMID: 31955250 DOI: 10.1007/s11274-020-2801-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/08/2020] [Indexed: 12/16/2022]
Abstract
Microbial fuel cells (MFCs) have emerged as a promising technology for sustainable wastewater treatment coupled with electricity generation. A MFC is a device that uses microbes as catalysts to convert chemical energy present in biomass into electrical energy. Among the various mechanisms that drive the operation of a MFC, extracellular electron transfer (EET) to the anode is one of the most important. Exoelectrogenic bacteria can natively transfer electrons to a conducting surface like the anode. The mechanisms employed for electron transfer can either be direct transfer via conductive pili or nanowires, or mediated transfer that involves either naturally secreted redox mediators like flavins and pyocyanins or artificially added mediators like methylene blue and neutral red. EET is a mechanism wherein microorganisms extract energy for growth and maintenance from their surroundings and transfer the resulting electrons to the anode to generate current. The efficiency of these electron transfer mechanisms is dependent not only on the redox potentials of the species involved, but also on microbial oxidative metabolism that liberates electrons. Attempts at understanding the electron transfer mechanisms will boost efforts in giving rise to practical applications. This article covers the various electron transfer mechanisms involved between microbes and electrodes in microbial fuel cells and their applications.
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76
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Light SH, Méheust R, Ferrell JL, Cho J, Deng D, Agostoni M, Iavarone AT, Banfield JF, D’Orazio SEF, Portnoy DA. Extracellular electron transfer powers flavinylated extracellular reductases in Gram-positive bacteria. Proc Natl Acad Sci U S A 2019; 116:26892-26899. [PMID: 31818955 PMCID: PMC6936397 DOI: 10.1073/pnas.1915678116] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mineral-respiring bacteria use a process called extracellular electron transfer to route their respiratory electron transport chain to insoluble electron acceptors on the exterior of the cell. We recently characterized a flavin-based extracellular electron transfer system that is present in the foodborne pathogen Listeria monocytogenes, as well as many other Gram-positive bacteria, and which highlights a more generalized role for extracellular electron transfer in microbial metabolism. Here we identify a family of putative extracellular reductases that possess a conserved posttranslational flavinylation modification. Phylogenetic analyses suggest that divergent flavinylated extracellular reductase subfamilies possess distinct and often unidentified substrate specificities. We show that flavinylation of a member of the fumarate reductase subfamily allows this enzyme to receive electrons from the extracellular electron transfer system and support L. monocytogenes growth. We demonstrate that this represents a generalizable mechanism by finding that a L. monocytogenes strain engineered to express a flavinylated extracellular urocanate reductase uses urocanate by a related mechanism and to a similar effect. These studies thus identify an enzyme family that exploits a modular flavin-based electron transfer strategy to reduce distinct extracellular substrates and support a multifunctional view of the role of extracellular electron transfer activities in microbial physiology.
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Affiliation(s)
- Samuel H. Light
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Raphaël Méheust
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720
- Innovative Genomics Institute, Berkeley, CA 94704
| | - Jessica L. Ferrell
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298
| | - Jooyoung Cho
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298
| | - David Deng
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Marco Agostoni
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
| | - Anthony T. Iavarone
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
- QB3/Chemistry Mass Spectrometry Facility, University of California, Berkeley, CA 94720
| | - Jillian F. Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720
- Innovative Genomics Institute, Berkeley, CA 94704
| | - Sarah E. F. D’Orazio
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky, Lexington, KY 40536-0298
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
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77
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Edwards MJ, Richardson DJ, Paquete CM, Clarke TA. Role of multiheme cytochromes involved in extracellular anaerobic respiration in bacteria. Protein Sci 2019; 29:830-842. [PMID: 31721352 PMCID: PMC7096707 DOI: 10.1002/pro.3787] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 01/08/2023]
Abstract
Heme containing proteins are involved in a broad range of cellular functions, from oxygen sensing and transport to catalyzing oxidoreductive reactions. The two major types of cytochrome (b-type and c-type) only differ in their mechanism of heme attachment, but this has major implications for their cellular roles in both localization and mechanism. The b-type cytochromes are commonly cytoplasmic, or are within the cytoplasmic membrane, while c-type cytochromes are always found outside of the cytoplasm. The mechanism of heme attachment allows for complex c-type multiheme complexes, having the capacity to hold multiple electrons, to be assembled. These are increasingly being identified as secreted into the extracellular environment. For organisms that respire using extracellular substrates, these large multiheme cytochromes allow for electron transfer networks from the cytoplasmic membrane to the cell exterior for the reduction of extracellular electron acceptors. In this review the structures and functions of these networks and the mechanisms by which electrons are transferred to extracellular substrates is described.
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Affiliation(s)
- Marcus J Edwards
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - David J Richardson
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
| | - Catarina M Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Oeiras, Portugal
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, UK
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78
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Wang W, Du Y, Yang S, Du X, Li M, Lin B, Zhou J, Lin L, Song Y, Li J, Zuo X, Yang C. Bacterial Extracellular Electron Transfer Occurs in Mammalian Gut. Anal Chem 2019; 91:12138-12141. [PMID: 31512863 DOI: 10.1021/acs.analchem.9b03176] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
As a well-studied biochemical reduction process in environmental microbiology, extracellular electron transfer (EET) was recently discovered in bacteria closely related to human health, and orthologues of a flavin-based EET gene were found in the genomes of many species across Firmicutes, a major phylum in mammalian gut microbiota. However, EET has not yet been confirmed to occur in mammalian gut, the presence of which may have broad physiological influences. Toward this end, here we first confirmed the occurrence of EET in mouse gut microbiotas cultured in vitro. Cyclic voltammetry analysis was then performed by directly inserting electrodes into the mouse cecum under anaerobic conditions, and a characteristic catalytic wave was observed in the gut of conventional but not germ-free mouse, proving the existence of in vivo bacterial EET. We also detected similar catalytic waves in the cecal microbiotas of rat and guinea pig in vivo, suggesting EET's high prevalence in mammalian intestines. Our finding on the bacterial electron production in mammalian guts offers a new bioelectrochemical scope for deciphering the complex microbiology of gut bacteria and its effects on host physiology.
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Affiliation(s)
- Wei Wang
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Yahui Du
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Biology, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Shuai Yang
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Xiaochen Du
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Min Li
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Bingqian Lin
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Biology, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Jie Zhou
- College of Biological Science and Engineering , Fuzhou University , Fuzhou 350116 , China
| | - Liyuan Lin
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Yanling Song
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Juan Li
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China.,College of Biological Science and Engineering , Fuzhou University , Fuzhou 350116 , China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Chaoyong Yang
- Institute of Molecular Medicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China.,The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Biology, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
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Gurumurthy DM, Bharagava RN, Kumar A, Singh B, Ashfaq M, Saratale GD, Mulla SI. EPS bound flavins driven mediated electron transfer in thermophilic Geobacillus sp. Microbiol Res 2019; 229:126324. [PMID: 31491671 DOI: 10.1016/j.micres.2019.126324] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/09/2019] [Accepted: 08/23/2019] [Indexed: 12/23/2022]
Abstract
Through extracellular electron transfer (EET), bacteria are capable of transforming different insoluble materials of geochemical interest into energy-rich molecules for their growth. For this process, bacteria have been depending directly or indirectly on molecules synthesized within the cells or by various synthetics as mediators. Herein, we studied the in-situ change in electrochemistry and supporting components for EET in the extracellular polysaccharide (EPS) producing biofilm of thermophilic Geobacillus sp. The CV and DPV resultsrevealed that the intact biofilm of bacteria was not able to generate any potential at 25 °C /- ≤50 °C. However, at 55 °C (optimal condition), the potential occurred drastically after the EPS production by bacteria. HPLC and MALDI-TOF results revealed that the presence of Flavins, which can able adsorbed to the electrodes from the cell surface. Moreover, the temperature-dependent EPS production and originally conceived ability of flavins to act as electron shuttles suggest that not much complexity in bacteria with minerals. Additionally, the electrochemical potential was severely affected upon removal of EPS/flavin moiety from the intact biofilm, revealed the necessity of EPS bound flavins in transferring the electrons across its thick cell walls. This paradigm shift to electrogenic nature of Geobacillus sp. biofilm will become evident in the adaptation of other microbes during mineral respiration in extreme environments.
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Affiliation(s)
| | - Ram Naresh Bharagava
- Department of Microbiology (DM), School for Environmental Sciences (SES), Babasaheb BhimraoAmbedkar University (A Central University), VidyaVihar, Raebareli Road, Lucknow 226 025, Uttar Pradesh, India
| | - Ashok Kumar
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India
| | - Bhaskar Singh
- Department of Environmental Sciences, Central University of Jharkhand, Ranchi, 835205, Jharkhand, India
| | - Muhammad Ashfaq
- Department of Chemistry, University of Gujrat, Gujrat, 50700, Pakistan
| | - Ganesh Dattatraya Saratale
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Sikandar I Mulla
- Department of Biochemistry, School of Applied Sciences, REVA University, Bangalore, 560 064, Karnataka State, India.
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