FURI | Spring 2023

Tracking the Metabolic Respiration of Geobacter lovleyi, a Dechlorinating and Metal Reducing Bacterium Relevant to Bioremediation

Hexavalent uranium (U(VI)) industrial processing typically requires chlorinated solvents and CAHs, such as tetrachloroethene (PCE), for the purpose of cleaning machinery. Because of this, the co-contamination of U(VI) and PCE can be found at several Superfund sites. Geobacter lovleyi strain SZ is the only reductive bacteria identified as being capable of reducing PCE to 1,2-cis-Dichloroethene (cis-DCE) while simultaneously reducing U(VI) to sparingly soluble U(IV). The objective of this research is to study the kinetics and metabolic pathways of G. lovleyi during respiration of U(VI) and PCE under different substrate conditions. The findings highlighted are from these experiments on G. lovleyi that resulted in the tracking of G. lovleyi kinetics, morphology, and transcriptomics. It was found that G. lovleyi under substrate conditions with excess fumarate had increased dechlorination kinetics and appeared to be somewhat oxygen tolerant, despite previously being considered a strict anaerobe. This suggests that there are ways to increase the effectiveness of reduction with G. lovleyi by changing substrate conditions. Recommendations for future work include testing higher acetate to fumarate ratios and further studying the effects of oxygen levels on G. lovleyi’s ability to grow and reduce contaminants.