Related Experiment Video
Updated: May 10, 2026

Characterizing Electron Transport through Living Biofilms
Published on: June 1, 2018
Redox mediator enhanced simultaneous decolorization of azo dye and bioelectricity generation in air-cathode microbial
Jian Sun1, Wanjun Li, Youming Li
1State Key Lab of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640, China. sunjian472@163.com
Abstract:
Enhanced simultaneous decolorization of Congo red and bioelectricity generation with anthraquinone-2,6-disulphonic disodium salt (AQDS), riboflavin (RF) and humic acid (HA) as mediators in air-cathode microbial fuel cell (MFC) was demonstrated. Compared with mediator-free MFC, the MFC with added 0.005 mM AQDS, 0.005 mM RF or 1g/L HA showed 36%, 26% and 15% increase in maximum power density along with 394%, 450%, and 258% increases in decolorization rates of Congo red, respectively. Addition of mediators at higher concentration further increased power and Congo red decolorization but the increases were not proportional to the rise in mediator concentration. Based on decreases of anode charge transfer resistance and increases of Congo red decolorization, the mediators kinetically promote the extracellular electron transfer between bacteria, anode and Congo red. Microbial analysis showed that addition of mediators changed the composition of anodic microbial community and stimulated the growth of species belonging to Chlorobi, Endomicrobia and Firmicutes.
Related Concept Videos
Anoxygenic Photosynthesis
Voltaic/Galvanic Cells
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Microbial Leaching
Microbes and Other Elemental Cycles
Redox Reactions
The Z-Scheme of Electron Transport in Photosynthesis

