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

Abstract

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 0 -dimethyl-4,4 0 -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.

Thylakoid Terminal Oxidases Are Essential for the CyanobacteriumSynechocystissp. PCC 6803 to Survive Rapidly Changing Light Intensities

“…The amount of chlorophyll was measured to determine photobleaching by subtracting the 750-nm OD value from the 680-nm OD value and multiplying the total by 10.854. There was a strong correlation (r 2 = 0.9854) in determining chlorophyll concentration between this method and the well-established chlorophyll quantification protocol as described previously (Porra et al, 1989;Bombelli et al, 2011;Supplemental Fig. S3).…”

Phycobilisome-Deficient Strains of Synechocystis sp. PCC 6803 Have Reduced Size and Require Carbon-Limiting Conditions to Exhibit Enhanced Productivity

“…Therefore, drawing any reliable comparison between our results and those of Kwon et al (2013) is not possible. However, the olive mutant may be useful for applications that require higher photosynthetic capacity, such as the generation of hydrogen (McCormick et al, 2013) or electricity in a biophotovoltaic device (Bombelli et al, 2011;Bradley et al, 2013).…”

“…value from the 680-nm O.D. value and multiplying by 10.854, as described previously (Bombelli et al, 2011;Lea-Smith et al, 2013).…”

Iron reduction by the cyanobacterium Synechocystis sp. PCC 6803

“…This latter approach was adopted in a recent paper by McCormick et al [20], who utilised Synechocystis sp 6803 and its interaction with ferricyanide to produce hydrogen. Various other devices created using Synechocystis and ferricyanide to produce electricity have additionally been reported [19,23]. Although the use of artificial mediators has widely been abandoned in microbial fuel cell operation due to sustainability issues, ferricyanide is still a valuable tool for investigations on metabolic activity.…”