Microbial Fuel Cell Based on Ensifer meliloti

The world’s growing energy crisis demands renewable energy sources. This issue can be solved using microbial fuel cells (MFCs). MFCs are biocatalytic systems which convert chemical energy into electrical energy, thereby reducing pollution from hazardous chemical compounds. However, during the development of MFCs, one of the most significant challenges is finding and assessment of microorganisms that generate sufficient redox potential through metabolic and catalytic processes. In this research, we have used Ensifer meliloti (E. meliloti) bacteria to design MFCs based on consecutive action of two redox mediators (9,10 - phenanthrenequinone (PQ) and potassium ferricyanide), which transferred charge between E. meliloti bacteria and graphite rod electrode. A viability study of E. meliloti culture showed that PQ significantly inhibits the growth of bacteria at 0.036 mM. Cyclic voltammograms were registered in the presence of 20 mM of potassium ferricyanide and different concentrations (0.036 and 0.071 mM, 0.11 mM, 0.14 mM, 0.172 mM, 0.32 mM) of PQ. Four days of lasting assessment of the microbial fuel cells in two-electrode systems showed that the maximal open circuit potential during the experiment raised from 174.9 to 234.6 mV. Power increased from 0.392 to 0.741 mW m −2 .