Stability and reliability of anodic biofilms under different feedstock conditions: Towards microbial fuel cell sensors

•A continuously fed system facilitated non-cumulative steady states of anodic biofilms.•Different substrates, when swapped, consistently generated reproducible MFC power outputs.•Anodic biofilm metabolic activity responded in a dynamic manner to different substrates.•Repeated exposure to different feedstocks increases substrate versatility.

Stability and reliability of microbial fuel cell anodic biofilms, consisting of mixed cultures, were investigated in a continuously fed system. Two groups of anodic biofilm matured with different substrates, acetate and casein for 20–25 days, reached steady states and produced 80–87 μW and 20–29 μW consistently for 3 weeks, respectively. When the substrates were swapped, the casein-enriched group showed faster response to acetate and higher power output, compared to the acetate-enriched group. Also when the substrates were switched back to their original groups, the power output of both groups returned to the previous levels more quickly than when the substrates were swapped the first time. During the substrate change, both MFC groups showed stable power output once they reached their steady states and the output of each group with different substrates was reproducible within the same group. Community level physiological profiling also revealed the possibility of manipulating anodic biofilm metabolisms through exposure to different feedstock conditions.