Microbial Fuel Cell Biosensors

Microbial fuel cells work by converting chemical energy in the chemical bonds of organic compound to electrical energy through catalytic reactions of micro-organisms under anaerobic conditions. In the chamber, the anode short-circuits the natural electrons acceptors. The protons then pass through the proton-selective membrane towards the aerobic chamber. The electrons produced are transferred to the cathode, here they reduce oxygen to form water. Electrons transfer from the microbial cell to the anode occurs either via membrane-associated components or via soluble electron shuttles termed mediators. Figure 1 shows a scheme of a microbial fuel cell.

For my experiment, I would be covering two parts:

1. I will be investigating how different concentrations of organic matter in lake water obtained from Leazes Park will affect current density output. Concentration of organic matter would be changed by addition of glucose to the lake water.

2. I will be verifying the hypothesis that concentration of organic matter in a microbial fuel cell is linearly proportional to its current output. For this experiment, lactate is used as the organic matter and its concentration is varied.

Current challenges faced are the long time required to obtain a measurement (more than 24hrs). During my project, I will be looking into improving the efficiency of the microbial fuel cell system by the addition of substrate chitin to test if the hypothesis holds true.

For more information please contact Dr Sharon Valesquez-Orta.

Fig. 1 - Microbial fuel cell system. Taken from Biological Fuel Cells. Wordpress. Web.17 Oct 2012. http://biologicalfuelcell.wordpress.com/biological-fuel-cells