Metal Ions Influence on Shewanella Oneidensis MR-1 Adhesion to ITO Electrode and Enhancement Current Output

2020 ◽  
Vol MA2020-01 (47) ◽  
pp. 2690-2690
Author(s):  
Aisha Alshahrani ◽  
Alanah Fitch ◽  
John Al-Bazi
Keyword(s):  
Metal Ions ◽  
Shewanella Oneidensis ◽  
Current Output ◽  
Ito Electrode

Electron Transfer of Shewanella Oneidensis MR-1 atClay-Modified ITO Electrode

2020 ◽  
Vol MA2020-01 (47) ◽  
pp. 2688-2688
Author(s):  
Reem Alshehri ◽  
Alanah Fitch
Keyword(s):  
Electron Transfer ◽  
Shewanella Oneidensis ◽  
Ito Electrode

scholarly journals Behavior of Shewanella oneidensis MR-1 in a sulfur and zinc-rich medium and its applications for biosensing and biomaterials

2019 ◽  
Author(s):  
James Dylan Rees ◽  
Yuri Gorby ◽  
Shayla Sawyer
Keyword(s):  
Metal Ion ◽  
Electrochemical Impedance ◽  
Solid Phase ◽  
Shewanella Oneidensis ◽  
Metal Sulfide ◽  
Ion Concentration ◽  
Metallic Ions ◽  
Anaerobic Conditions ◽  
Oxidation Activity ◽  
Current Output

An increasing focus of current microbiology research is the fact that some strains of bacteria, called dissimilatory metal-reducing bacteria (DMRB), are capable of utilizing certain metallic ions as terminal electron acceptors in their metabolic processes. One strain in particular, Shewanella oneidensis MR-1, can reduce ions of iron, lead, arsenic, and uranium, among others. Under anaerobic conditions it has also been shown to reduce sulfur compounds, nitrates, and chromates. The cultivation of DMRB under controlled conditions therefore has significant implications for the low-energy, room-temperature synthesis of metal sulfide and/or metal oxide semiconductors. Furthermore, Shewanella and other DMRB can form biofilms that interact electronically with solid-phase minerals in their environment. For this reason there exists a potential to grow DMRB directly into porous substrates in order to create biosensors that are capable of producing electrical signals that provide information about metal ion concentration in water as well as a range of other water quality variables.I will highlight my recent work exploring the behavior of Shewanella oneidensis MR-1, in a medium rich in both zinc and thiosulfate ions. I have grown Shewanella bacteria in a three-electrode system and used a potentiostat to hold the system at a fixed DC voltage during cultivation while also measuring current output. After completing the cultivation step, I have used cyclic voltammetry and electrochemical impedance spectroscopy to characterize the DC and AC current-voltage dynamics of the system, which can reveal the reduction-oxidation activity of key bacterial proteins. In the second experiment, I have grown Shewanella bacteria under both aerobic and anaerobic conditions in media rich in zinc and thiosulfate ions and used scanning electron microscopy and energy dispersive microscopy to characterize the minerals that precipitate within the batches. I compare results from a minimal medium containing only the zinc and thiosulfate sources to a more traditional Shewanella medium containing various vitamins, minerals and other nutrients to support growth. I also compare the inoculated batches to sterile control batches containing no bacteria in order to infer the effect that the bacteria have on mineralization in their environment. Finally, I use confocal microscopy to explore the fluorescence behavior of the precipitates generated in both inoculated and sterile batches.

scholarly journals Biosynthesis of Molybdenum Disulfide Nanoparticles Using The Metal-Reducing Bacterium Shewanella Oneidensis MR-1

2019 ◽  
Author(s):  
James Dylan Rees ◽  
Shayla Sawyer ◽  
Yuri Gorby
Keyword(s):  
Electron Microscopy ◽  
New York ◽  
Metal Ions ◽  
Molybdenum Disulfide ◽  
Shewanella Oneidensis ◽  
Anaerobic Respiration ◽  
Synthesis Methods ◽  
Layered Semiconductor ◽  
Terminal Electron Acceptor ◽  
Indirect Band Gap

The bacterium Shewanella oneidensis MR-1 is a dissimilatory metal-reducing bacterium capable of performing anaerobic respiration using a metal as terminal electron acceptor. Isolated from Lake Oneida in Upstate New York, S. oneidensis MR-1 was first noted for its manganese-reducing capability, but has now been shown to reduce a range of metal ions such as Fe(III), Mn(IV), As(V) and Cr(VI), as well as sulfur anions such as thiosulfate and sulfite. In the lab, Shewanella has been grown anaerobically in media enhanced with sulfur and metal ions in order to produce several types of chalcogenide nanoparticles, such as zinc sulfide and arsenic trisulfide.Given the utility of chalcogenide materials for electronics and photonics applications, bacterially-synthesized chalcogenide nanoparticles present a tantalizing avenue for green chemistry. Compared to similar materials produced using traditional chemical synthesis methods, bacterially-synthesized nanomaterials can be produced at much lower temperatures and using fewer chemical reagents. This work presents a method of synthesizing molybdenum disulfide nanoparticles using S. oneidensis bacteria. Molybdenum disulfide is a layered semiconductor with an indirect band gap in its bulk state and a direct bandgap in its monolayer state. It also exhibits changes in its electronic properties when its surfaces are functionalized with molecules, giving it applications for both photodetection and biosensing. An anaerobic batch culture of S. oneidensis MR-1 was incubated at room temperature in the presence of molybdenum oxide, resulting in the production of molybdenum disulfide crystals less than a micron in diameter. These crystals were detected using scanning electron microscopy, transmission electron microscopy, absorbance spectroscopy and X-ray diffraction. In addition to confirming that molybdenum disulfide can be produced by Shewanella bacteria, the data collected using these methods provide insight on the size, morphology and photoresponse of nanoparticles generated this way. The findings also allow inferences to be made about how the confluence of several mechanisms present in an anaerobic Shewanella culture combine to make such a synthesis possible, while providing clues about how such processes can be further improved or extended to other materials.

Study on Impact Factors of Reducing U(VI) by S. oneidensis

2014 ◽  
Vol 1065-1069 ◽  
pp. 3287-3290
Author(s):  
Jin Xiang Liu ◽  
Shui Bo Xie ◽  
Yong Hua Wang ◽  
Shi You Li ◽  
Biao Li
Keyword(s):  
Metal Ions ◽  
Removal Rate ◽  
Shewanella Oneidensis ◽  
Impact Factors ◽  
Initial Concentration ◽  
Low Concentration ◽  
Reduction Efficiency ◽  
Coexisting Ions

Impact Factors of reducing U(VI) by the Shewanella oneidensis Were studied in this study. The results showed S. oneidensis has highly resistant to acid and Uranium. U(VI) initial concentration has the very big influence on reduction of U(VI) and the optimum U(VI) concentration is 30mg/Lwith removal rate of 95.02% at 4 days, Metal ions Cu2+,Mn2+ and Ca2+ impact on the reduction of U(VI). equal concentrations of Cu2+ and Mn2+ could cause varying degrees of inhibition of U(VI) reduction, Ca2+ acted as a weak role in promoting the reduction, the coexisting ions of SO42-and low concentration of no3-(<0.5mmol/L) did not markedly influence the reduction efficiency of U(VI). zero alent iron (ZVI) can accelerate the reduction of U(VI) by the S. oneidensis .

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

ELNES of Iron Compounds

1990 ◽  
Vol 48 (2) ◽  
pp. 28-29
Author(s):  
Hiroki Kurata ◽  
Kazuhiro Nagai ◽  
Seiji Isoda ◽  
Takashi Kobayashi
Keyword(s):  
Energy Loss ◽  
Metal Ions ◽  
Energy Resolution ◽  
Transition Metal Oxides ◽  
Local Symmetry ◽  
Iron Compounds ◽  
Fine Structures ◽  
Electron Energy Loss ◽  
Fe Ions ◽  
Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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