Quantitative analysis of the factors limiting solar power transduction by Synechocystis sp. PCC 6803 in biological photovoltaic devices

Recent advances in fuel cell (FC) and microbial fuel cell (MFC) research have demonstrated these electrochemical technologies as effective methods for generating electrical power from chemical fuels and organic compounds. This led to the development of MFC-inspired photovoltaic (BPV) devices that produce electrical power by harvesting solar energy through biological activities of photosynthetic organisms. We describe the fabrication of a BPV device with multiple microchannels. This allows a direct comparison between sub-cellular photosynthetic organelles and whole cells, and quantitative analysis of the parameters affecting power output. Electron transfer within the photosynthetic materials was studied using the metabolic inhibitors DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and methyl viologen (1,1'-dimethyl-4,4'-bipyridinium dichloride). These experiments suggest that the electrons that cause an increase in power upon illumination leave the photosynthetic electron transfer chain from the reducing end of photosystem I. Several key factors limiting performance efficiency, including density of the photosynthetic catalyst, electron carrier concentration, and light intensity were investigated.