A new approach for evaluating electron transfer dynamics by using in-situ resonance Raman microscopy and chronoamperometry in conjunction with a dynamic model.

A new approach for evaluating electron transfer dynamics by using in-situ resonance Raman microscopy and chronoamperometry in conjunction with a dynamic model. Appl Environ Microbiol. 2020 Aug 21;: Authors: Krige A, Ramser K, Sjöblom M, Christakopoulos P, Rova U Abstract Geobacter sulfurreducens is a good candidate as a chassis-organism due to its ability to form thick, conductive biofilms, enabling long distance extracellular electron transfer (EET). Due to the complexity of EET pathways in G. sulfurreducens, a dynamic approach is required to study genetically modified EET rates in the biofilm. By coupling on-line resonance Raman microscopy with chronoamperometry, we were able to observe the dynamic discharge response in the biofilm's cytochromes to an increase in anode voltage. Measuring the heme redox state alongside the current allows for the fitting of a dynamic model using the current response and a subsequent validation of the model via the value of a reduced cytochrome c Raman peak. The modelled reduced cytochromes closely fitted the Raman response data from the G. sulfurreducens wild-type strain, showing the oxidation of heme groups in cytochromes until achieving a new steady state. Furthermore, the use of a dynamic model also allows for the calculation of internal rates, such as acetate and NADH consumption rates. The Raman response of a mutant lacking OmcS showed a sharper initial rate than predicted, followed by an almos...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research