Microbial fuel cells (MFCs) have emerged as a promising bioelectrochemical technology for sustainable energy generation and environmental protection. By utilizing electrochemically active microorganisms, MFCs convert organic matter, including biomass and waste, into electricity [1]. Additionally, certain organic pollutants can serve as electron donors or acceptors, enabling simultaneous energy production and pollutant removal. While oxygen is commonly used as an electron acceptor due to its high oxidation potential and availability, ongoing research explores alternative acceptors to enhance system efficiency [2]. As the global shift toward renewable energy becomes imperative due to the environmental impact of fossil fuels, MFCs offer a dual benefit of clean energy generation and waste treatment. This technology holds significant potential for addressing energy demands while contributing to a more sustainable future [3].
The symbiosis between E. meliloti and legumes enables nitrogen fixation, initiated by plant-released betaines and flavonoids that attract the bacteria to root hairs. E. meliloti secretes nod factors, forming infection threads and bacteroids in root nodules [4]. Nitrogen fixation occurs only in the endosymbiotic state, with leghemoglobin regulating oxygen for nitrogenase activity [5].
This study explores the application of E. meliloti in MFCs and examines charge transfer mechanisms between bacteria and electrodes in real agricultural samples. The process is enhanced by various quinone mediators acting as lipophilic redox mediators, aiming to improve electron transfer efficiency and overall MFC performance.