Photoautotrophic microalgae Scenedesmus obliquus attached on a cathode as oxygen producers for microbial fuel cell (MFC) operation

• Microalgae Scenedismus obliquus biofilm on cathode was able to support MFC operation.
• MFC with algal aeration exhibited higher power than with mechanical aeration.
• DO concentration with algae on the cathode increased to a maximum of 15.7 mg/L.
• The cathode internal resistance decreased with time in algal aeration.
• CV of cathode during algal aeration revealed higher reduction current of −9.3 mA.

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 Ω external resistance. In polarization test, MFC with algal aeration exhibited the maximum power density of 153 mW/m2, which was 32% higher than the value (116 mW/m2) 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 Ω) and charge transfer resistance (9.6–7.2 Ω) 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).

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