Uranium Biomineralization as a Result of Bacterial Phosphatase Activity: Insights from Bacterial Isolates from a Contaminated Subsurface

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• 作者：Melanie J. Beazley ; Robert J. Martinez ; Patricia A. Sobecky ; Samuel M. Webb ; Martial Taillefert
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：August 15, 2007
• 年：2007
• 卷：41
• 期：16
• 页码：5701 - 5707
• 全文大小：168K
• 年卷期：v.41,no.16(August 15, 2007)
• ISSN：1520-5851

文摘

Uranium contamination is an environmental concern atthe Department of Energy's Field Research Center in OakRidge, Tennessee. In this study, we investigated whetherphosphate biomineralization, or the aerobic precipitation ofU(VI)-phosphate phases facilitated by the enzymaticactivities of microorganisms, offers an alternative to themore extensively studied anaerobic U(VI) bioreduction. Threeheterotrophic bacteria isolated from FRC soils werestudied for their ability to grow and liberate phosphate inthe presence of U(VI) and an organophosphate betweenpH 4.5 and 7.0. The objectives were to determine whetherthe strains hydrolyzed sufficient phosphate to precipitateuranium, to determine whether low pH might have an effecton U(VI) precipitation, and to identify the uranium solidphase formed during biomineralization. Two bacterial strainshydrolyzed sufficient organophosphate to precipitate 73-95% total uranium after 120 h of incubation in simulatedgroundwater. The highest rates of uranium precipitation andphosphatase activity were observed between pH 5.0 and7.0. EXAFS spectra identified the uranyl phosphate precipitateas an autunite/meta-autunite group mineral. The resultsof this study indicate that aerobic heterotrophic bacteriawithin a uranium-contaminated environment that canhydrolyze organophosphate, especially in low pH conditions,may play an important role in the bioremediation ofuranium.