Shelobolina Evgenya S, Konishi Hiromi, Xu Huifang, Roden Eric E
Department of Geology and Geophysics, 1215 W. Dayton St., University of Wisconsin, Madison, WI 53706, USA.
Appl Environ Microbiol. 2009 Sep;75(18):5773-8. doi: 10.1128/AEM.00628-09. Epub 2009 Jul 24.
Previous studies have demonstrated the potential for removal of U(VI) from solution via precipitation of U(VI)-bearing calcium-phosphate (Ca-P) minerals coupled to microbial hydrolysis of glycerol phosphate compounds. We evaluated this process in circumneutral-pH groundwater from Area 2 of the U.S. Department of Energy Field Research Center at Oak Ridge National Laboratory. Area 2 groundwater contains high concentrations of dissolved calcium (ca. 4 mM), and thus, release of phosphate during glycerol phosphate metabolism has the potential to create conditions favorable for U(VI) sequestration in Ca-P minerals. Microbial enumeration and isolation studies verified the presence of aerobic and nitrate-reducing glycerol 3-phosphate (G3P)-metabolizing microorganisms in Area 2 sediments. Coprecipitation of U(VI) with Ca-P minerals coupled to microbial G3P hydrolysis was demonstrated in artificial groundwater under aerobic and nitrate-reducing conditions. Transmission electron microscopy analysis and mineral-washing experiments demonstrated that U(VI) was incorporated into the structure of the insoluble Ca-P mineral hydroxyapatite [Ca5(PO4)3OH]. Our results support the idea that U(VI) can be effectively removed from solution in contaminated aquifers through stimulation of microbial organophosphate metabolism.
先前的研究表明，通过含铀（VI）的磷酸钙（Ca-P）矿物沉淀并结合微生物对甘油磷酸化合物的水解作用，有可能从溶液中去除铀（VI）。我们在美国能源部橡树岭国家实验室现场研究中心2区的近中性pH值地下水中评估了这一过程。2区地下水含有高浓度的溶解钙（约4 mM），因此，甘油磷酸代谢过程中磷酸盐的释放有可能创造有利于铀（VI）在Ca-P矿物中螯合的条件。微生物计数和分离研究证实了2区沉积物中存在好氧和硝酸盐还原型甘油3-磷酸（G3P）代谢微生物。在好氧和硝酸盐还原条件下，人工地下水中证明了铀（VI）与Ca-P矿物的共沉淀以及微生物对G3P的水解作用。透射电子显微镜分析和矿物洗涤实验表明，铀（VI）被纳入不溶性Ca-P矿物羟基磷灰石[Ca5(PO4)3OH]的结构中。我们的结果支持这样一种观点，即通过刺激微生物有机磷代谢，可以有效地从受污染含水层的溶液中去除铀（VI）。
