(537d) Modeling Cellular Metabolism and U(VI) Immobilization In Shewanella Oneidensis MR-1 Biofilms

Uranium (U) contamination of the environment due to nuclear processing activities causes significant economic and health problems due to its presence in terrestrial and aquatic ecosystems. Understanding the mobility of U at the microscale is critical for predicting its macroscale fate and for optimizing remediation strategies. Mathematical modeling can provide a non-intrusive and low-cost alternative to difficult and expensive laboratory and field experiments. In this study, we developed a 2-dimentionsal mathematical model to monitor U mobility inside Shewanella oneidensis MR-1 biofilms. Biofilms are comprised of a matrix of cells and abundant extracellular polymeric substances (EPS), both loosely-associated and bound EPS. Specifically, our model focused on (1) the contribution of cells and EPS to immobilize U, (2) the effect of U on cellular metabolism and EPS production, and (3) the relative role of adsorption and reduction on overall U immobilization. The model was developed and solved using COMSOL Multiphysics software. Our model demonstrated that U preferentially binds to specific locations within the biofilm, which U detrimentally affects cellular metabolism, and that loosely associated and bound EPS interact differently with U.