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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