Exploring the effect of Shewanella oneidensis outer membrane redox proteins in the electrochemical response of single blocking impact events

Single blocking impacts electrochemistry was used to explore the redox properties of the outer membrane proteins of the Gram-negative electroactive bacteria Shewanella oneidensis on disk -shaped ultramicroelectrodes. We report a comparative study of blocking impact experiments with E. coli DH5 alpha and two strains of S. oneidensis MR -1 (the wild -type strain SOMR1 and the mutant Delta MtrC Delta OmcA where the MtrC and OmcA outer membrane cytochromes genes were deleted from the genome) based on chronoamperometry measurements recorded in ferrocyanide as a redox probe at +0.8 V vs Ag/AgCl on carbon fiber, Pt and Au ultramicroelectrodes. The data analysis was performed by calculating the change of standard deviation of the background current values measured before and after the first three impact events for each bacterial strain. Compared to others, SOMR1 bacteria increases the magnitude of current fluctuations in the i - t curves after the first current step because of the outer membrane redox proteins activity at the polarized ultramicroelectrode surface. The role of the S. oneidensis ' outer membrane c -type cytochromes redox proteins in the adhesion of electroactive bacteria onto a polarized surface is highlighted by blocking impacts electrochemistry at the single -cell scale for the first time in this work.