FIGURE 1.

(A) Current vs. time measurements for microbial current generation by Acidithiobacillus ferrooxidans cells on an fluorine-doped tin oxide (FTO) electrode in the absence of Fe²⁺ ions (solid line) at +0.4 V (vs. SHE). Current vs. time measurements without cells at +0.4 V was also depicted as a reference (broken line) (B) Effects of the deep-UV (254 nm) irradiation to the microbial current generation by the cells in the absence of Fe²⁺ ions at +0.4 V (solid line). Current vs. time measurements without cells at +0.4 V was also depicted as a reference (broken line). (C) In-situ optical microscope observation of an FTO electrode surface at the indicated time (panel A) after cell inoculation. (D) Plot of microbial current against cell number attached on an electrode surface obtained from in-situ optical microscope observation (panels A and B). The squares of the correlation coefficients were estimated by the addition of the point of origin to the obtained data. The geometric area of the FTO electrode was 3.14 cm². Initial OD₅₀₀ was 0.02.