As climate change intensifies and greenhouse gas emissions increase, there is growing global interest in finding sustainable solutions. A microbial fuel cell (MFC) is a bioelectrochemical system that can transform chemical energy into electrical energy, contributing to the reduction of pollution caused by harmful chemical compounds. This method emerged as a promising technology to address energy and environmental challenges by generating renewable energy [2].
Ensifer meliloti is a nitrogen-fixing bacterium that forms a symbiotic relationship with plants. The process begins when plant releases betaines and flavonoids that attract E. meliloti to root hairs. The bacteria then penetrate the root, forming nodules where they can develop into bacteroids, only then nitrogen fixation occur. Leghemoglobin, produced by the plant, regulates oxygen levels to maintain nitrogenase activity. These natural mechanisms could be adapted for microbial fuel cell [1]. MFCs utilize microbial catalysis to facilitate electron transfer, enhancing their efficiency in energy production. The use of redox mediators, such as quinones, is particularly significant, as they help improve electron flow between microbes and electrodes, advancing MFC performance. This mechanism makes MFCs a viable solution for clean energy generation while simultaneously addressing environmental concerns and reducing of pollutants [3].
This research aims to investigate the electrochemical behavior of Ensifer meliloti in microbial fuel cell while determining the efficiency of electron transfer and assessing its interaction with redox mediators, including various quinones and a K\(_{3}\)[Fe(CN)\(_{6}\)] solution.