| Uranium contamination in groundwater from waste created in the production of nuclear energy is a problem that can be solved with a bioremediation bioreactor. Investigating the reduction and oxidation reactions and the biotransformation of uranium will aid in the development of a suitable bioreactor. Under aerobic conditions the metal reducing bacteria Shewanella oneidensis directly reduces soluble hexavalent uranium to insoluble tetravalent uranium. Microbial reduction of hexavalent uranium by Shewanella oneidensis is dependent on c-type cytochromes and extracellular pili protein structures. This study investigates whether a higher yield of uranium can be removed from water treated with bioreactors containing Shewanella oneidensis and graphene oxide encapsulated in alginate. Biomass and graphene oxide was embedded in a calcium-alginate matrix to immobilize uranium and remove it from aqueous solution. The variables tested included calcium-alginate beads encapsulated Shewanella oneidensis and graphene oxide, only S. oneidensis, only graphene oxide, and absence of both. Two hundred milliliters of a 500 part per million uranyl nitrate solution was cycled through bioreactors for one hundred twenty minutes and ten milliliter samples were removed at fifteen minute intervals. Bioreactor models removed nearly 70% uranium from solution within fifteen minutes showing maximum sorption more than 90%.;KEY WORDS: Bioreactor, bioremediation, biosorption, biotransformation. |
