Specific industries result in a reoccurring contamination of uranium in soil and groundwater, which poses a threat when accumulated through the food chain. The severity of this accumulation depends on the mobility of uranium. Microorganisms can influence uranium mobility, toxicity and distribution. In turn, uranium exerts a permanent pressure on the prevailing microbial community, disruption microbial communities and processes. Fundamental understanding of the interaction between microorganisms and uranium is essential to assess the microbial impact in contaminated environments correctly. Moreover, knowledge on the underlying cellular response can be exploited to improve bioremediation technologies. We sampled and analyzed a contaminated site and showed that long-term metal and radionuclide pollution impacts the microbial community structure and functionality. In addition, an important part of this study investigated uranium resistance mechanisms in Cupriavidus metallidurans. C. metallidurans NA4 was able to remove uranium from growth medium as uranium-phosphate complexes associated with PHB via an active mechanism and we explained the transcriptomic changes underlying uranium exposure. Moreover, rapid evolution towards a significantly increased uranium resistance was observed in C. metallidurans NA4. Deletion of czcS2 coding for the sensor kinase of the two-component system CzcR2-CzcS2 results in increased transcriptional expression of the response regulator CzcR2. CzcR2 on its turn cross-activated the expression of prsQ2 coding for a small periplasmic protein resulting in the increased uranium resistance. Finally, exploratory studies were performed to use C. metallidurans for metal and uranium removal.
|Qualification||Doctor of Science|
|Date of Award||27 Jan 2022|
|State||Published - 27 Jan 2022|