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Team:Bielefeld-CeBiTec/Project/rMFC/Mediators
From 2014.igem.org
rMFC
Neutral Red
Neutral red (3-Amino-7-dimethylamino-2-methylphenazine hydrochloride) is a phenazine-based dye which is normally used as pH-indicator due to the fact that it changes its colour from red (pH 6.8) to yellow (pH 8.0).
Besides that it could be shown that reduced neutral red is also capable as the sole source of reducing power for growth and metabolism of H2 consuming bacteria cultures.(Park, D. H. & Zeikus, J. G. 2000)
The chemical structure is shown in figure 1.
Figure 1: Chemical structure of the triphenylmethane dye neutral red.
There is also evidence that electrically reduced neutral red can bind to the cell membrane and chemically reduces NAD. Furthermore it is not toxic to the cells and can replace H2 which is the natural electron shuttle for some bacteria species. (Park et al., 1999)
Bromphenol Blue
Bromphenolblue is a triarylmethane dye that is similar to neutral red and also capable to function as mediator.
Figure 2: Chemical structure of the triphenylmethane dye bromphenol blue.
Cytochromes
Cytochromes are proteins containing a heme group. They are primarly responsible for the electron transport in the respiratory chain.References
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Park, D. H. & Zeikus, J. G. (2000) Electricity generation in microbial fuel cells using neutral red as an electronophore. In: Applied and Environmental Microbiology, 66 (4), pp. 1292 - 1297.
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Azariah, A. N., Berchmans, S., Yegnaraman (1998) Electrochemical behaviour of neutral red. Bulletin of Electrochemistry. , 14 (10), pp. 309-314
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Park, D. H.,Laivenieks, M., Guettler, M. V., Jain, M. K. & Zeikus, J. G. (1999) Microbial utilization of electrically reduced neutral red as the sole electron donor for growth and metabolic production. In: Appl. Environ. Microbiol., 65 (7), pp. 2912 - 2917.
