Investigating the Role of a Less Uranium Tolerant Strain, Isolated from the Hanford Site Soil, on Uranium Interaction in Polyphosphate Remediation Technology

Abstract

Bacteria are key players in the processes that govern fate and transport of contaminants. Previous assessment showed that the Arthrobacter oxydans (A.oxydans) G968 strain has a lower ability to tolerate U(VI) toxicity in bicarbonate-free media compared to other isolate A.oxydans G975. The study experimentally investigated several parameters such as the potential of bicarbonate to accelerate U(VI) release from autunite mineral in the presence of a less U(VI) tolerant bacterial strain, in the conditions mimicking Hanford Site subsurface environments. Results showed that despite morphological differences between the two bacterial strains, A.oxydans G968 and G975, they are able to dissolute uranium at the same capacity. The effect of both bacterial strands on autunite dissolution reduces as the concentration of bicarbonate increases. AFM and viability studies showed that samples containing bicarbonate are able to acclimate and withstand uranium toxicity. This study provides a better understanding of the bacterial role in polyphosphate remediation technology and interactions between meta-autunite and microbes.