Authors: Aisha Alshahrani, Alanah Fitch, John Al-Bazi
The goal of this study is to enhance the efficiency of bacterial extracellular electron transfer (EET) in Shewanella oneidensis MR-1 by enhancing adhesion to the electrode surface. Our results clearly show a major difference in attachment and behavior of S. oneidensis MR-1 for Ca2+, Pb2+, Cd2+, and Mg2+ compared to the control. The final microbial coverage, as measured by confocal microscopy and cathodic peak charge in cyclic voltammetry (Qpc), increases with increasing metal ion concentrations. We found the cells attached to the electrode increased more with the addition of metal ion concentrations in the following order of metals: Ca22+ > Pb2+ > Cd2+ > Mg2+ compared to the control. The effect of metal ions on metabolism of the bacteria was tested by the riboflavin production and glucose consumption. Metabolic activity mirrored the same order of the activity as the electrochemical results.
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