Abstract A microbial fuel cell whose anode was steeped directly in a cultivating liquid was demonstrated to work long term by adding nutrients periodically. A fairly large current density (ca. 60 μA/cm2) was obtained by using a stainless-steel net electrode plated with platinum black. The electroactivities of glucose and metabolites produced by Enterobacter aerogenes were analysed by the single scan voltammogram method. From the analysis, it was found that the main anode reactant was hydrogen which was biochemically produced from glucose by the bacteria.