Photoautotrophic algae Scenedismus obliquus could attach on the surface of a cathode electrode and produced oxygen for electricity generation in microbial fuel cell (MFC). Oxygen concentration by algae aeration in the cathode chamber increased from 0 to 15.7 mg/l within 12-h, and a voltage generation of 0.47 +/- 0.03 V was obtained with 1000 Omega external resistance. In polarization test, MFC with algal aeration exhibited the maximum power density of 153 mW/m(2), which was 32% higher than the value (116 mW/m(2)) with mechanical aeration at oxygen concentration of 5.9 mg/l. The internal resistance of MFC with algal aeration decreased in ohmic resistance (5.9-5.2 Omega) and charge transfer resistance (9.6 -7.2 Omega) over 72-h operation. Cyclic voltammetry of cathode during algal aeration revealed higher reduction current of -9.3 mA compared to mechanical aeration (-4.7 mA). Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.