Tracking of Shewanella oneidensis MR-1 biofilm formation of a microbial electrochemical system via differential pulse voltammetry

In this study, the electrochemical properties of a Shewanella oneidensis MR-1 biofilm were investigated using a mini-microbial electrochemical system. The performance of the biofilm was shown, using discharge test and cyclic voltammetry investigations, to improve over time. Differential pulse voltammograms were also acquired to determine the type of extracellular electron transfer that took place and to characterize the structure of the microbial biofilm formed on the electrode of the electrochemical system. These results indicated that extracellular electron transfer via a flavin-like mediator chemical predominated as the biofilm grew. The results, combined with a comparison of the measured current density with the calculated value of a seamless single-layered biofilm, also suggested that S. oneidensis MR-1 formed a multi-layered biofilm on the electrode.