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Gao L, Lu X, Liu H, Li J, Li W, Song R, Wang R, Zhang D, Zhu J. Mediation of Extracellular Polymeric Substances in Microbial Reduction of Hematite by Shewanella oneidensis MR-1. Front Microbiol 2019; 10:575. [PMID: 30984128 PMCID: PMC6449630 DOI: 10.3389/fmicb.2019.00575] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/06/2019] [Indexed: 12/30/2022] Open
Abstract
Extracellular electron transfer (EET) plays a fundamental role in microbial reduction/oxidation of minerals. Extracellular polymeric substances (EPS) surrounding the cells constitute a matrix that separates the cell's outer membrane from insoluble minerals and environmental fluid. This study investigated the effects of EPS on EET processes during microbial reduction of hematite by the iron-reducing strain Shewanella oneidensis MR-1 (MR-1). Electrochemical characterization techniques were employed to determine the influence of EPS components on the redox ability of MR-1. Cells with removed EPS exhibited approximately 30% higher hematite reduction than regular MR-1 cells, and produced a current density of 56 μA cm-2, corresponding to 3-4 fold that of regular MR-1. The superior EET of EPS-deprived cells could be attributed to direct contact between outer membrane proteins and hematite surface, as indicated by more redox peaks being detected by cyclic voltammetry and differential pulse voltammetry. The significantly reduced current density of MR-1 cells treated with proteinase K and deoxyribonuclease suggests that the electron transfer capacity across the EPS layer depends mainly on the spatial distribution of specific proteins and electron shuttles. Exopolysaccharides in EPS tend to inhibit electron transfer, however they also favor the attachment of cells onto hematite surfaces. Consistently, the charge transfer resistance of cells lacking EPS was only 116.3 Ω, approximately 44 times lower than that of regular cells (5,139.1 Ω). These findings point to a negative influence of EPS on EET processes for microbial reduction/oxidation of minerals.
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Affiliation(s)
- Lei Gao
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Xiancai Lu
- Key Laboratory of Surficial Geochemistry, Ministry of Education, Nanjing University, Nanjing, China
| | - Huan Liu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Juan Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Weijie Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Rongbin Song
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Ruiyong Wang
- School of Life Sciences, Nanjing University, Nanjing, China
| | - Dongmei Zhang
- School of Life Sciences, Nanjing University, Nanjing, China
| | - Junjie Zhu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
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Molecular underpinnings for microbial extracellular electron transfer during biogeochemical cycling of earth elements. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1275-1286. [DOI: 10.1007/s11427-018-9464-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/09/2018] [Indexed: 02/07/2023]
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Arinda T, Philipp LA, Rehnlund D, Edel M, Chodorski J, Stöckl M, Holtmann D, Ulber R, Gescher J, Sturm-Richter K. Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms. Front Microbiol 2019; 10:126. [PMID: 30804910 PMCID: PMC6370747 DOI: 10.3389/fmicb.2019.00126] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/21/2019] [Indexed: 11/17/2022] Open
Abstract
Shewanella oneidensis is one of the best-understood model organisms for extracellular electron transfer. Endogenously produced and exported flavin molecules seem to play an important role in this process and mediate the connection between respiratory enzymes on the cell surface and the insoluble substrate by acting as electron shuttle and cytochrome-bound cofactor. Consequently, the addition of riboflavin to a bioelectrochemical system (BES) containing S. oneidensis cells as biocatalyst leads to a strong current increase. Still, an external application of riboflavin to increase current production in continuously operating BESs does not seem to be applicable due to the constant washout of the soluble flavin compound. In this study, we developed a recyclable electron shuttle to overcome the limitation of mediator addition to BES. Riboflavin was coupled to magnetic beads that can easily be recycled from the medium. The effect on current production and cell distribution in a BES as well as the recovery rate and the stability of the beads was investigated. The addition of synthesized beads leads to a more than twofold higher current production, which was likely caused by increased biofilm production. Moreover, 90% of the flavin-coupled beads could be recovered from the BESs using a magnetic separator.
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Affiliation(s)
- Tutut Arinda
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Laura-Alina Philipp
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - David Rehnlund
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Miriam Edel
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jonas Chodorski
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Markus Stöckl
- Electrochemistry, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Dirk Holtmann
- Industrial Biotechnology, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Roland Ulber
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Johannes Gescher
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute for Biological Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Katrin Sturm-Richter
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Kim TY, Kim MG, Lee JH, Hur HG. Biosynthesis of Nanomaterials by Shewanella Species for Application in Lithium Ion Batteries. Front Microbiol 2018; 9:2817. [PMID: 30524408 PMCID: PMC6258770 DOI: 10.3389/fmicb.2018.02817] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/02/2018] [Indexed: 11/13/2022] Open
Abstract
Nanomaterials exhibit extraordinary properties based on their size, shape, chemical composition, and crystal structure. Owing to their unique properties nanomaterials are preferred over their bulk counterparts for a number of applications. Although conventional physical and chemical routes were established for the massive production of nanomaterials, there are some drawbacks such as environmental burden and high cost that cannot be disregarded. Recently, there has been great interest toward the green synthesis of inorganic nanomaterials. It has been reported that dissimilatory metal reduction by microorganisms is a cost-effective process to remediate toxic organic and inorganic compounds under anaerobic conditions. Particularly, members of the Shewanella genus have been utilized to produce various biogenic nanomaterials with unique micro/nanostructured morphologies through redox transformations as well as to remove harmful metals and metalloids in eco-efficient and environment-friendly methods under ambient conditions. In the present mini-review, we specifically address the active utilization of microbial respiration processes for the synthesis of novel functional biogenic nanomaterials by the members of the Shewanella genus. This biosynthetic method may provide alternative approaches to produce electrode materials for sustainable energy storage applications.
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Affiliation(s)
- Tae-Yang Kim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Min Gyu Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, South Korea
| | - Ji-Hoon Lee
- Department of Bioenvironmental Chemistry, Chonbuk National University, Jeonju, South Korea
| | - Hor-Gil Hur
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
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