A novel miniaturized terrestrial microbial fuel cell reveals rapid electrochemical signals

In this study, a novel miniature terrestrial microbial fuel cells (TMFCs) inoculated with commercial garden soil was developed to generate bioelectricity. The startup and stabilization were evaluated as open circuit voltage (OCV). The effect of an enrichment procedure with 12 mM, 37 mM, and 61 mM Na-acetate under anaerobic conditions was assessed. The initial OCV was 0.55 ± 0.02 V, 0.58 ± 0.01 V and 0.75 ± 0.15 V in the TMFCs inoculated with 12 mM, 37 mM and 61 mM Na-acetate, respectively. The OCV increased in relation with the substrate input. The average OCV during stable operation was as follows: 1.01 ± 0.006 V (12 mM), 1.02 ± 0.005 V (37 mM) and 1.13 ± 0.003 V (61 mM). The time required for peaking the maximum voltage and its stabilization was significantly decreased up to ~2 h. Hence, it is concluded that the OCV output of the miniature TMFCs was comparable or even higher than macroscale reactors and it is optimal for rapid detection of the electrogenic process in soil samples. Furthermore, the reactor design displayed simplicity and the electrode area to reactor volume ratio was enhanced in contrast to macroscale TMFCs.