Figure 1

Current generation and metabolite concentrations in the cellulose-fed two-chambered MFC. Closed circle, electric current (mA); open square, pH in the anode chamber; closed square, acetate in the anode chamber (mM); closed diamond, propionate in the anode chamber (mM); open triangle, methane in the anode chamber. Methane concentration was expressed as 'mM equivalent (eq.)' by supposing that all methane was present in the aqueous phase. Broken lines represent times when the anode electrode was transferred to new anode chambers, solid stars indicate times when cellulose (6 g l^-1) was added to the anode chambers, while arrows indicate times when pH in the anode chamber was adjusted to 7.0. The arrowhead indicates the time when the cathode chamber was supplemented with potassium ferricyanide.