Understanding the Role of the Bacteria, Isolated from the Hanford Site Soil, on the Fate and Transport of Uranium

Bacteria are known for their abilities to influence the geochemical processes and affect the mobility of contaminants in the subsurface. Arthrobacter strain G975 was studied to improve our understanding of their effect on uranium’s fate and transport. The research experimentally identified and compared several parameters, including cell growth rate, cell viability, and the bacteria partition coefficient, Kd, under various uranium and bicarbonate concentrations mimicking Hanford Site subsurface environmental conditions, as well as the microbes ability to interact with uranyl phosphate minerals. The results show that the G975 strain can uptake up to 90% of the U(VI) concentrations tested, following linear isotherm models whose uptake capacity was measured up to 150.2 ± 71.4 mg/g and decreased with increasing bicarbonate concentrations. AFM and SEM/EDS analysis confirmed surface membrane uranium precipitates. The research presented here is part of a large effort to advance the understanding of the biogeochemistry processes and plausible remediation strategies concerning uranium contamination