Reduction Kinetic of Water Soluble Metal Salts by Geobacter sulfurreducens: Fe2+/Hemes Stabilize and Regulate Electron Flux Rates

Frontiers in Microbiology

Jörn Dengjel²  Michael Stumpe²  Maksym Karamash³  Bernd Giese³  Katharina M. Fromm³  Carlos A. Salgueiro⁴ 

[1] Associate Laboratory i4HB – Institute for Health and Bioeconomy, School of Science and Technology, NOVA University Lisbon, Costa da Caparica, Portugal;Department of Biology, University of Fribourg, Fribourg, Switzerland;Department of Chemistry, University of Fribourg, Fribourg, Switzerland;UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department, School of Science and Technology, NOVA University Lisbon, Costa da Caparica, Portugal;

关键词: reaction kinetic;    c-cytochrome;    Geobacter sulfurreducens;    remediation;    bioelectrochemistry;   

DOI  :  10.3389/fmicb.2022.909109

来源: DOAJ

【 摘 要 】

Geobacter sulfurreducens 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 c-cytochromes on the electron flux during respiration of G. sulfurreducens, the reduction kinetic of Fe3+, Co3+, V5+, Cr6+, and Mn7+ containing complexes were measured. Starting from the resting phase, each G. sulfurreducens cell produced an electron flux of 3.7 × 105 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 c-cytochrome concentrations by downregulation and mutation demonstrated that c-cytochromes stabilized respiration rates by variation of their redox states. Increasing Fe2+/heme levels increased electron flux rates, and induced respiration flexibility. The kinetic effects parallel electrochemical results of G. sulfurreducens biofilms on electrodes, and might help to optimize bioelectrochemical devices.

【 授权许可】

Unknown