[SCAN] Elucidation of the electron transfer processes in exoelectrogens

Scan Seminar

Title: Elucidation of the electron transfer processes in exoelectrogens

Speaker: Catarina Paquete

From: Inorganic Biochemistry and NMR Lab, ITQB

Abstract:

Numerous bacteria have evolved strategies that allow them to sustain growth in anaerobic conditions through the respiratory reduction of insoluble compounds. This metabolic capability enables their use not only for sustainable energy production, such as in microbial fuel cells (MFC), but also for bioremediation of contaminated environments. A wide variety of bacteria, including both Gram-negative and Gram-positive bacteria, were shown to be able to perform extracellular electron transfer, and thus capable to generate energy in MFC. Multiheme c-type cytochromes (MHC) were found to be the main components in the extracellular electron transfer pathways in these bacteria, enabling electrons to flow from the cell metabolism toward outside of the cell, for the reduction of insoluble compounds or electrodes. Although much research have been performed to exploit extracellular electron transfer processes, the mechanisms by which these bacteria perform this type of respiration are still largely unknown. To understand these processes, it is necessary to characterize in detail the electron transfer mechanisms of the proteins involved in the extracellular electron transfer pathways. In this presentation, the thermodynamic and kinetic properties of several MHC involved in these electron transfer processes will be presented. This information is essential not only to understand how exoelectrogens perform extracellular electron transfer but also to maximize power output in MFC and to make these devices a practical sustainable energy resource.