2.4. MFC Operation

The anolyte (TSB mixed with inoculum at a volumetric ratio of 1:1 for the start-up) and catholyte solutions were continuously supplied using a syringe pump (KD Scientific) at rates of 3 μL/min and 5 μL/min, respectively, to anode and cathode chambers, independently. The catholyte was 100 mM potassium ferricyanide (K₃[Fe(CN)₆], Sigma-Aldrich) in a 100 mM phosphate buffer, in which the pH was adjusted at 7.5 ± 0.1. The µMFC was operated at 25 ± 1 °C. Different µMFC assemblies were connected to 25 kΩ external loads or operated under open circuit voltage conditions. The potential between the anode and cathode was measured via a digital multimeter (Agilent 3441A, Keysight Technologies) with a data acquisition system and recorded results every 1 min via a Keysight IntuiLink interface. All of the systems were operated under anaerobic conditions via the help of sealing gaskets between the anode and cathode chambers. The characteristics of µMFC systems operated in the study are presented in Table 1.

µMFC systems operated in the study.