Chromium has been used extensively in the industry process of metal refinishing and electroplating. It is also a byproduct of the processing of fissionable materials at United States Department of Energy facilities. Chromate (Cr (VI)) is soluble and readily absorbed by cells, while the reduced form of chromium, Cr (III), is insoluble. Thus means of reducing Cr (VI) to Cr (III) in the environment is a potential means of remediation. Desulfovibrio desulfuricans strain 27774 is a sulfate reducing bacterium that can reduce Cr (VI). It also can respire nitrate to ammonia. As some sites of chromium contamination also contain high concentrations of nitrate, an investigation of Cr (VI) reduction under nitrate reducing growth conditions by D. desulfuricans strain 27774 was conducted. A growth medium that was compatible with the colorimetric assay for Cr (VI) and did not itself reduce Cr (VI) was formulated. Cell assays determined that Cr (VI) reduction was primarily in the supernatant, catalyzed by a secreted secondary metabolite. A genomics investigation identified two pathways as possible mechanisms. / Bayer School of Natural and Environmental Sciences / Environmental Science and Management (ESM);= / MS / Thesis
| Identifer | oai:union.ndltd.org:DUQUESNE/oai:digital.library.duq.edu:etd/154133 |
| Date | 27 April 2013 |
| Creators | Zhang, Ning |
| Contributors | John F. Stolz, Tobin J. Michael, Skip H.M. Kingston |
| Source Sets | Duquesne University |
| Detected Language | English |
| Rights | One year embargo: no access to PDF file until release date by author request. |
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