Figure 5. Electrode potential and pH dependency of enhancement factor in the microbial current production of S. oneidensis MR-1 determined by the addition of either 2 μM riboflavin (RF) or flavin mononucleotide (FMN).

(a) The current production was compared before and after flavin addition at pH 7.8 at electrode potentials of −0.2, 0.4 and 0.8 V vs. SHE. (b) The current production was compared before and after flavin addition at an electrode potential of 0.4 V at pH 5.6, 7.3, 7.8 and 8.6. Error bars indicate the standard error of the mean values calculated with data obtained from three or more individual experiments.