title: In situ uranium stabilization by microbial metabolites.
abstract: Microbial melanin production by autochthonous bacteria was explored in this study as a means to increase U immobilization in U contaminated soil. This article demonstrates the application of bacterial physiology and soil ecology for enhanced U immobilization in order to develop an in situ, U bio-immobilization technology. We have demonstrated microbial production of a metal chelating biopolymer, pyomelanin, in U contaminated soil from the Tims Branch area of the Department of Energy (DOE), Savannah River Site (SRS), South Carolina, as a result of tyrosine amendments. Bacterial densities of pyomelanin producers were >10(6) cells per g wet soil. Pyomelanin demonstrated U complexing and mineral binding capacities at pH 4 and 7. In laboratory studies, in the presence of goethite or illite, pyomelanin enhanced U sequestration by these minerals. Tyrosine amended soils in a field test demonstrated increased U sequestration capacity following pyomelanin production up to 13 months after tyrosine treatments.
authors.affiliation: Environmental Science and Biotechnology, Savannah River National Laboratory, Building 999W, Aiken, SC 29808, USA. Charles.Turick@srnl.doe.gov
authors.forename: Charles E
authors.initials: CE
authors.lastname: Turick
authors.forename: Anna S
authors.initials: AS
authors.lastname: Knox
authors.forename: Chad L
authors.initials: CL
authors.lastname: Leverette
authors.forename: Yianne G
authors.initials: YG
authors.lastname: Kritzas
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D004787:Environmental Pollution / Q000032:analysis / Q000517:prevention & control; D008543:Melanins / Q000378:metabolism; D008903:Minerals / Q000737:chemistry; D012988:Soil Microbiology; D012990:Soil Pollutants, Radioactive / Q000032:analysis* / Q000378:metabolism; D013022:South Carolina; D014501:Uranium / Q000032:analysis* / Q000378:metabolism
chemical_list: D008543:Melanins; D008903:Minerals; D012990:Soil Pollutants, Radioactive; C023793:pyomelanin; C099089:illite; D014501:Uranium