Finneran, Kevin T University of Illinois at Urbana-Champaign

Complete Reductive Dechlorination of Trichloroethylene (TCE) by non-Dehalococcoides Microorganisms

The objectives of the proposed work are to: 1) demonstrate that organisms outside of the genus Dehalococcoides can completely reduce TCE to ethene, 2) use the enrichment cultures developed to characterize the metabolism, geochemistry, and chlorinated solvent biodegradation kinetics of non-Dehalococcoides microorganisms, 3) verify that the dominant non-Dehalococcoides microorganism(s) are most closely related to organisms within the genus Desulfosporosinus, 4) characterize the pathway for acetate oxidation and utilization during complete dechlorination to determine if it is directly oxidized as the sole electron donor (by Dehalococcoides or non-Dehalococcoides liquid enrichment cultures) or to define the mechanisms by which it may generate hydrogen under the same conditions, 5) demonstrate that electron donors (acetate or H2) added at stoichiometric concentrations relative to the electron acceptors present promotes faster TCE reduction to ethene when compared to excess electron donor addition, and 6) quantify the specific conditions in which Fe(III) reduction and complete dechlorination are promoted simultaneously.

This is the first research to address the probability of non-Dehalococcoides complete dechlorination. This will change fundamental and applied science and engineering with respect to halorespiration as a metabolic process, and chlorinated solvent bioremediation as a practiced technology. In addition, the work will characterize several poorly understood environmental processes including the overlap of Fe(III) reduction and complete dechlorination, and acetate as a direct electron donor for halorespiration. The proposal has been constructed in a manner that all hypotheses are relevant and independent, and the data generated will benefit the broader scientific community studying basic halorespiration science or those investigating applied bioremediation of TCE.

The proposed outreach plan incorporates both students who are members of underrepresented groups in environmental engineering, and practitioners who will ultimately benefit from the data. The students will be both graduate level and undergraduate level, and will be recruited specially from programs for minority and female students. The practitioner aspect will culminate in direct contact with one group who has already expressed interest in the work and with others via conferences and individual presentations to small groups at their regional offices. Entire research staff including the proposed postdoctoral scholar will interact with all practitioners such that they become accustom to the lab to field transition for research, and how the pragmatic aspects of environmental engineering practice can influence fundamental research science.

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Clemson University
United States
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