An in-situ surface electrochemistry approach toward whole-cell studies: Charge transfer between Geobacter sulfurreducens and electrified metal/electrolyte interfaces through linker molecules

Kuzume, Akiyoshi; Zhumaev, Ulmas; Li, Jianfeng; Fu, Yongchun; Füeg, Michael; Esteve-Nuñez, Abraham; Wandlowski, Thomas (2013). An in-situ surface electrochemistry approach toward whole-cell studies: Charge transfer between Geobacter sulfurreducens and electrified metal/electrolyte interfaces through linker molecules. Electrochimica acta, 112, pp. 933-942. Elsevier Science 10.1016/j.electacta.2013.02.073

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Electrochemical reactivity and structure properties of electrogenic bacteria, Geobacter sulfurreducens (Gs) were studied to explore the heterogeneous electron transfer at the bacteria/electrode interface using electrochemical and in-situ spectroscopic techniques. The redox behavior of Gs adsorbed on a gold electrode, which is modified with a ω-functionalized self-assembled monolayer (SAM) of alkanethiols, depends strongly on the terminal group. The latter interacts directly with outermost cytochromes embedded into the outer membrane of the Gs cells. The redox potential of bacterial cells bound electrostatically to a carboxyl-terminated SAM is close to that observed for bacteria attached to a bare gold electrode, revealing a high electronic coupling at the cell/SAM interface. The redox potentials of bacterial cells adsorbed on amino- and pyridyl-terminated SAMs are significantly different suggesting that the outermost cytochromes changes their conformation upon adsorption on these SAMs. No redox activity of Gs was found with CH3-, N(CH3)3+- and OH-terminated SAMs. Complementary in-situ spectroscopic studies on bacteria/SAMs/Au electrode assemblies were carried out to monitor structure changes of the bacterial cells upon polarization. Spectro-electrochemical techniques revealed the electrochemical turnover of the oxidized and reduced states of outer membrane cytochromes (OMCs) in Gs, providing evidence that the OMCs are responsible for the direct electron transfer to metal electrodes, such as gold or silver, during the electricity production. Furthermore, we observed spectroscopic signatures of the native structure of the OMCs and no conformational change during the oxidation/reduction process of the microorganisms. These findings indicate that the carboxyl-anchoring group provides biocompatible conditions for the outermost cytochromes of the Gs, which facilitate the heterogeneous electron transfer at the microorganism/electrode interface.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Kuzume, Akiyoshi; Zhumaev, Ulmas; Li, Jianfeng; Fu, Yongchun; Füeg, Michael and Wandlowski, Thomas

Subjects:

500 Science > 540 Chemistry
500 Science > 570 Life sciences; biology

ISSN:

0013-4686

Publisher:

Elsevier Science

Funders:

[UNSPECIFIED] European Union
[4] Swiss National Science Foundation
[UNSPECIFIED] University of Bern

Language:

English

Submitter:

Ulmas Zhumaev

Date Deposited:

17 Jan 2014 09:55

Last Modified:

11 Aug 2015 10:53

Publisher DOI:

10.1016/j.electacta.2013.02.073

Uncontrolled Keywords:

Geobacter sulfurreducens, Raman spectroscopy, IR spectroscopy, Cytochromes, Electron transport

BORIS DOI:

10.7892/boris.39813

URI:

https://boris.unibe.ch/id/eprint/39813

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