The MFCs were fed a 50:50 mixture of the inoculum and sodium acetate (1 g/L; J.T. Baker) in a buffer (50 mM phosphate buffer, PBS; Na2HPO4, 4.58 g/L; and NaH2PO4 ·H2O, 2.45 g/L, pH ) 7.0) and nutrient solution (NH4Cl, 0.31 g/L; KCl, 0.13 g/L; trace nutrient medium) (19