The two-chamber MFC was set-up by connecting two plastic bottles (10.0 cm in height and 3.5 cm in diameter) by a tube (4.0 cm in length and 2.0 cm in diameter) which contained a PEM (E-TEK) inside. Preparations of PEM and electrodes were done as described by Bond and Lovely [6]. In order to facilitate the growth of biofilm, carbon paper (2.0 cm×5.0 cm, E-TEK) with rough surface and porosity was placed in the anode chamber to accumulate the electron-transfering bacteria. A carbon cloth (2.0 cm×5.0 cm, E-TEK) was inserted into the cathode chamber to act as a cathode. In tests with oxygen in the cathode, a carbon cloth loaded with Pt catalysts (5% content and 0.4 mg cm−2, E-TEK) was used.