The aim of this work was to illustrate the use of photosynthetic microbes in a microbial fuel cell to produce electricity without the requirement of an external carbon source. This research here describes the use of a cyanobacterium Synechocystis PCC6803, to produce electricity without any net CO2 production in a two-chambered MFC. Conditions for optimum electricity production were determined through standardizing operating parameters. A maximum power density of 6.7 mW m(-3)(anode chamber volume) was achieved under high intensity lighting (10,000 lux). Light intensity and wavelength directly affected electricity production, indicating the pivotal role played by photosynthesis. The maximum removal of CO2 was 625 mmol m(-3) over 20 h under high intensity light. The results presented here will contribute to the understanding of how cyanobacteria can be exploited for the direct conversion of CO2 to electric current. (C) 2012 Elsevier Ltd. All rights reserved.