scholarly journals Protamine Promotes Direct Electron Transfer Between Shewanella Oneidensis Cells and Carbon Nanomaterials in Bacterial Biocomposites

2019 ◽  
Vol 6 (9) ◽  
pp. 2349-2349
Author(s):  
Stéphane Pinck ◽  
Frédéric P. A. Jorand ◽  
Mengjie Xu ◽  
Mathieu Etienne
Keyword(s):  
Electron Transfer ◽  
Carbon Nanomaterials ◽  
Direct Electron Transfer ◽  
Shewanella Oneidensis

scholarly journals Rational Surface Modification of Carbon Nanomaterials for Improved Direct Electron Transfer-Type Bioelectrocatalysis of Redox Enzymes

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1447
Author(s):  
Hongqi Xia ◽  
Jiwu Zeng
Keyword(s):  
Electron Transfer ◽  
Surface Modification ◽  
Recent Progress ◽  
Carbon Nanomaterials ◽  
Direct Electron Transfer ◽  
Rational Surface ◽  
Interfacial Electron Transfer ◽  
Redox Enzymes ◽  
Oriented Immobilization

Interfacial electron transfer between redox enzymes and electrodes is a key step for enzymatic bioelectrocatalysis in various bioelectrochemical devices. Although the use of carbon nanomaterials enables an increasing number of redox enzymes to carry out bioelectrocatalysis involving direct electron transfer (DET), the role of carbon nanomaterials in interfacial electron transfer remains unclear. Based on the recent progress reported in the literature, in this mini review, the significance of carbon nanomaterials on DET-type bioelectrocatalysis is discussed. Strategies for the oriented immobilization of redox enzymes in rationally modified carbon nanomaterials are also summarized and discussed. Furthermore, techniques to probe redox enzymes in carbon nanomaterials are introduced.

The conjugated oligoelectrolyte DSSN+ enables exceptional coulombic efficiency via direct electron transfer for anode-respiring Shewanella oneidensis MR-1—a mechanistic study

2014 ◽  
Vol 16 (38) ◽  
pp. 20436-20443 ◽  
Author(s):  
Nathan D. Kirchhofer ◽  
Xiaofen Chen ◽  
Enrico Marsili ◽  
James J. Sumner ◽  
Frederick W. Dahlquist ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Coulombic Efficiency ◽  
Direct Electron Transfer ◽  
Shewanella Oneidensis ◽  
Mechanistic Study ◽  
Electron Transfer Pathway

Biofilm electrochemistry reveals that DSSN+ increases coulombic efficiency by enhancing the native direct electron transfer pathway of S. oneidensis MR-1.

Protamine Promotes Direct Electron Transfer BetweenShewanella oneidensisCells and Carbon Nanomaterials in Bacterial Biocomposites

2019 ◽  
Vol 6 (9) ◽  
pp. 2398-2406
Author(s):  
Stéphane Pinck ◽  
Frédéric P. A. Jorand ◽  
Mengjie Xu ◽  
Mathieu Etienne
Keyword(s):  
Electron Transfer ◽  
Carbon Nanomaterials ◽  
Direct Electron Transfer

scholarly journals Flavin Electron Shuttles Dominate Extracellular Electron Transfer by Shewanella oneidensis

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicholas J. Kotloski ◽  
Jeffrey A. Gralnick
Keyword(s):  
Electron Transfer ◽  
Direct Electron Transfer ◽  
Shewanella Oneidensis ◽  
Phenotypic Characterization ◽  
Extracellular Electron Transfer ◽  
Wild Type ◽  
Content Type ◽  
Electron Shuttling ◽  
Electron Shuttles ◽  
Set Up

ABSTRACT Shewanella oneidensis strain MR-1 is widely studied for its ability to respire a diverse array of soluble and insoluble electron acceptors. The ability to breathe insoluble substrates is defined as extracellular electron transfer and can occur via direct contact or by electron shuttling in S. oneidensis. To determine the contribution of flavin electron shuttles in extracellular electron transfer, a transposon mutagenesis screen was performed with S. oneidensis to identify mutants unable to secrete flavins. A multidrug and toxin efflux transporter encoded by SO_0702 was identified and renamed bfe (bacterial flavin adenine dinucleotide [FAD] exporter) based on phenotypic characterization. Deletion of bfe resulted in a severe decrease in extracellular flavins, while overexpression of bfe increased the concentration of extracellular flavins. Strains lacking bfe had no defect in reduction of soluble Fe(III), but these strains were deficient in the rate of insoluble Fe(III) oxide reduction, which was alleviated by the addition of exogenous flavins. To test a different insoluble electron acceptor, graphite electrode bioreactors were set up to measure current produced by wild-type S. oneidensis and the Δbfe mutant. With the same concentration of supplemented flavins, the two strains produced similar amounts of current. However, when exogenous flavins were not supplemented to bioreactors, bfe mutant strains produced significantly less current than the wild type. We have demonstrated that flavin electron shuttling accounts for ~75% of extracellular electron transfer to insoluble substrates by S. oneidensis and have identified the first FAD transporter in bacteria. IMPORTANCE Extracellular electron transfer by microbes is critical for the geochemical cycling of metals, bioremediation, and biocatalysis using electrodes. A controversy in the field was addressed by demonstrating that flavin electron shuttling, not direct electron transfer or nanowires, is the primary mechanism of extracellular electron transfer employed by the bacterium Shewanella oneidensis. We have identified a flavin adenine dinucleotide transporter conserved in all sequenced Shewanella species that facilitates export of flavin electron shuttles in S. oneidensis. Analysis of a strain that is unable to secrete flavins demonstrated that electron shuttling accounts for ~75% of the insoluble extracellular electron transfer capacity in S. oneidensis.

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