A novel technique that allowed spatial transcriptional profiling of the current producing biofilm indicted that there was no significant difference in metabolism between the cells closet to the anode and those furthest from the electrode surface . Gene expression patterns suggest that the cells closet to the anode surface, while metabolic active, expressed a range of proteins commonly associated with environmental stress, expected to be a result of the proton accumulation. Interestingly the cell furthest from the anode did not express any genes commonly associated with electron acceptor limitation.