produced during 14 days of fermentation in both the second and
third batch fermentations were more than twice as large as that
produced in the first batch fermentation. The acetic acid yields
after 14 days of fermentation in the second and third batch
fermentations were 89.9% and 73.3%, respectively, which were
large and similar to that of acetic acid fermentation carried out
under aerated conditions (75.8%). The voltages for the MFC in the
second and third batch fermentations were continuous and
almost constant during fermentation (Fig. 6b and c). The
Coulombic efficiencies over the 14 days of the second and third
batch fermentations were 2.97% and 1.61%, respectively.