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Media type:
E-Article
Title:
Reduction Kinetic of Water Soluble Metal Salts by Geobacter sulfurreducens: Fe2+/Hemes Stabilize and Regulate Electron Flux Rates
Contributor:
Karamash, Maksym;
Stumpe, Michael;
Dengjel, Jörn;
Salgueiro, Carlos A.;
Giese, Bernd;
Fromm, Katharina M.
imprint:
Frontiers Media SA, 2022
Published in:Frontiers in Microbiology
Language:
Not determined
DOI:
10.3389/fmicb.2022.909109
ISSN:
1664-302X
Origination:
Footnote:
Description:
<jats:p><jats:italic>Geobacter sulfurreducens</jats:italic> is a widely applied microorganism for the reduction of toxic metal salts, as an electron source for bioelectrochemical devices, and as a reagent for the synthesis of nanoparticles. In order to understand the influence of metal salts, and of electron transporting, multiheme <jats:italic>c</jats:italic>-cytochromes on the electron flux during respiration of <jats:italic>G. sulfurreducens</jats:italic>, the reduction kinetic of Fe<jats:sup>3+</jats:sup>, Co<jats:sup>3+</jats:sup>, V<jats:sup>5+</jats:sup>, Cr<jats:sup>6+</jats:sup>, and Mn<jats:sup>7+</jats:sup> containing complexes were measured. Starting from the resting phase, each <jats:italic>G. sulfurreducens</jats:italic> cell produced an electron flux of 3.7 × 10<jats:sup>5</jats:sup> electrons per second during the respiration process. Reduction rates were within ± 30% the same for the 6 different metal salts, and reaction kinetics were of zero order. Decrease of <jats:italic>c</jats:italic>-cytochrome concentrations by downregulation and mutation demonstrated that <jats:italic>c</jats:italic>-cytochromes stabilized respiration rates by variation of their redox states. Increasing Fe<jats:sup>2+</jats:sup>/heme levels increased electron flux rates, and induced respiration flexibility. The kinetic effects parallel electrochemical results of <jats:italic>G. sulfurreducens</jats:italic> biofilms on electrodes, and might help to optimize bioelectrochemical devices.</jats:p>