Conference on Environmental Science and Technology

Microbial fuel cells (MFCs) represent a promising technology for sustainable electricity generation and wastewater treatment. However, their long-term efficiency is hindered by limited substrate availability for electroactive bacteria such as Shewanella oneidensis MR-1. This study introduces a three-layered MFC design incorporating MR-1 with Pseudomonas strains and ammonium-oxidizing bacteria (AOB) to enhance bioelectricity production. Extracellular polymeric substances (EPS) produced by AOB strains—particularly Nitrosomonas europaea and Nitrosococcus watsonii—were found to be rich in proteins and polysaccharides, serving as degradable organic substrates. Introducing Pseudomonas strains improved EPS breakdown, promoting MR-1 biofilm development and electron transfer efficiency. Peak power densities of 0.279 W/cm² and 0.204 W/cm² were achieved with S. oneidensis MR-1 + Pseudomonas putida + N. europaea and N. watsonii, respectively. In contrast, P. aeruginosa–based systems produced lower peaks (0.085 W/cm² and 0.059 W/cm²) but maintained power generation for longer durations—up to 68.5 hours. These results highlight a trade-off between power density and operational longevity, offering insights into tailoring microbial consortia for specific energy and treatment goals. The structured integration of MR-1, Pseudomonas, and AOB provides a scalable strategy for enhancing MFC performance in ammonium-rich wastewater environments.