2541
Electrolyte Effects on Shewanella Oneidensis MR-1 Loading and Cyclic Voltammetric Behavior at an ITO Electrode

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)

ABSTRACT WITHDRAWN

The goal of this study is understanding phenomena which may help design electrode modifications enhancing efficiency of microbial fuel cells. Our hypothesis is that the rate of deposition is proportional to both composition of the outer cell membrane and the bulk concentration. We also suggest that ionic strength and ion identity can affect the efficiency of sticking after initial encounter. Shown here are electrochemical studies on effect of salt concentration on S. oneidensis MR-1 attachment and growth at ITO electrodes. Initial surface coverage of bacteria can be measured with respect to four metric. One metric is the observed lag time before currents increase during bacterial loading at the ITO surface. A second one is the current associated with that lag time. The third is the maximum anodic current that occurs after the lag period. Finally a cyclic voltammetric experiment following loading has a metric associated with the cathodic peak current. The peak current is very large for NaCl compare to CsCl. The final coverage (as measured by cathodic peak current in cyclic voltammetry, ipc) increases with increasing ionic strength (IS). We suggest that the behavior of cathodic peak current is very sensitive to the salt concentrations and bacteria harvest time. Our results clearly show a major difference in attachment and behavior of S. oneidensis MR-1 for NaCl compared to CsCl. CsCl inhibits all four metrics associated with loading at +0.2 vs Ag/AgCl (lag time, lag current, maximum loading current and cyclic voltammetric peak current).