Burcu Unal and Ronald Hedden
Graduate Assistant, Materials Science and Engineering
The Pennsylvania State University
Rhizobia are aerobic bacteria that form symbiotic relationships with leguminous plants. Colonizing in root "nodules", they absorb nutrients from the plants while producing NH3 and H2 from atmospheric N2 and H2O (nitrogen fixation). Achieving nitrogen fixation ex-planta is challenging, due to stringent requirements of oxygen concentration and the need to continuously remove the product, NH3. We are designing a packed-bed, continuous flow bioreactor system for cultivation of Rhizobia under controlled environmental conditions. A key element in our reactor design is the packing material, polymeric hydrogels that can support growth of the bacteroids, while permitting transport of nutrients, waste products, and gaseous reactants at optimal rates.