The substrate types clearly affected the power density and
coulombic efficiency (CE). Acetate had the highest CE of
38%, followed by ethanol at 22% and glucose at 19%. Due
to the degradation of ethanol and glucose to other fermentation
products, the CE for these two substrates was lower
than CE of acetate.
The Andrew’s inhibition kinetics analysis indicated the substrate
inhibition for voltage generation at high concentration.
Cyclic voltammetry (CV) measurements demonstrated the
electrochemical properties of the anodes and showed a clear
correlation between peak heights and voltage generation.
The glucose-fed MFCs exhibited higher peaks than acetate
and ethanol. The peak heights increased at the substrate
concentrations of 0.5–8 mM, but then decreased at the concentrations
of 35 mM.
IV. A shorter electrode distance resulted in a lower internal
resistance and a higher voltage generation.
Ethanol showed the highest inhibition followed by
acetate and glucose.