Microbial fuel cell (MFC) powered by extracellular polysaccharides (EPS) from <i>salinoccocus roseus</i> for wastewater treatment and electricity production

Marine microorganisms live in severe environments, which causes them to create extracellular polysaccharides (EPS) in reaction to external stimuli. In this study, a marine bacterium was isolated from the Parangipettai Vellar estuary and sequenced to identify the organism as Salinococcus roseus, which can produce EPS. The ideal pH, carbon supply and nitrogen source for maximal EPS synthesis were identified as 7, glucose and ammonium sulfate, respectively. The FTIR examination of the EPS revealed polysaccharides, proteins, lipids and nucleic acid functional groups. The XRD study revealed that the EPS molecules are amorphous, whereas the surface morphology shows a continuous flat shape with fissures and folds. The created EPS was loaded into the agar bridge of the two-compartment microbial fuel cell (MFC). The voltage generated by the agar EPS bridge is just slightly higher than that of the ordinary agar salt bridge. The agar EPS bridge produced the most power (12[Formula: see text]mW/m 2 ) at a current density of 101[Formula: see text]mA/m 2 . The electrical output and treatment performance observed in this work arise from the nonlinear coupling between microbial reaction kinetics, charge transfer processes and variable-coefficient ion transport across the EPS bridge. Such nonlinear behavior is consistent with recent developments in nonlinear wave and transport analysis in inhomogeneous forced media, which provide a mathematical foundation for modeling EPS-mediated MFC systems. Similarly, the pH, conductivity and chemical oxygen demand (COD) removal rates were found to be higher in the EPS-loaded agar bridge, indicating that it is a better electron transfer medium. As a result, the EPS-driven MFC might be investigated further for use as a sustainable source of combined wastewater treatment and energy generation.