Studying microbial fuel cells equipped with heterogeneous ion exchange membranes: Electrochemical performance and microbial community assessment of anodic and membrane-surface biofilms

•Microbial fuel cells were tested with four ion exchange membranes (IEMs).•Anionic IEMs outperformed cationic ones at low acetate concentration.•Membrane selectivity determines the anodic biofilm microbial composition.•O2 crossover level (10-3–10-4 cm s−1) affects biofilm composition on the membrane.