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dc.contributor.authorSivaswamy, V.
dc.contributor.authorBoyanov, M. I.
dc.contributor.authorPeyton, Brent M.
dc.contributor.authorViamajala, Sridhar
dc.contributor.authorGerlach, Robin
dc.contributor.authorApel, William A.
dc.contributor.authorSani, Rajesh K.
dc.contributor.authorDohnalkova, Alice
dc.contributor.authorKemner, K. M.
dc.contributor.authorBorch, Thomas
dc.date.accessioned2017-02-07T16:18:48Z
dc.date.available2017-02-07T16:18:48Z
dc.date.issued2011-02
dc.identifier.citationSivaswamy V, Boyanov MI, Peyton BM, Viamajala S, Gerlach R, Apel WA, Sani RK, Dohnalkova A, Kemner KM, Borch T, "Multiple mechanisms of uranium immobilization by Cellulomonas sp. strain ES6," Biotechnology and Bioengineering, February 2011 108(2):264–276en_US
dc.identifier.issn0006-3592
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/12571
dc.description.abstractRemoval of hexavalent uranium (U(VI)) from aqueous solution was studied using a gram-positive facultative anaerobe, Cellulomonas sp. strain ES6, under anaerobic, non-growth conditions in bicarbonate and PIPES buffers.Inorganic phosphate was released by cells during the experiments providing ligands for formation of insoluble U(VI) phosphates. Phosphate release was most probably the result of anaerobic hydrolysis of intracellular polyphosphates accumulated by ES6 during aerobic growth. Microbial reduction of U(VI) to U(IV) was also observed. However, the relative magnitudes of U(VI) removal by abiotic (phosphate-based) precipitation and microbial reduction depended on the buffer chemistry. In bicarbonate buffer, X-ray absorption fine structure (XAFS) spectroscopy showed that U in the solid phase was present primarily as a non-uraninite U(IV) phase, whereas in PIPES buffer, U precipitates consisted primarily of U(VI)-phosphate. In both bicarbonate and PIPES buffer, net release of cellular phosphate was measured to be lower than that observed in U-free controls suggesting simultaneous precipitation of U and PO₄³⠻. In PIPES, U(VI) phosphates formed a significant portion of U precipitates and mass balance estimates of U and P along with XAFS data corroborate this hypothesis. High-resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray spectroscopy (EDS) of samples from PIPES treatments indeed showed both extracellular and intracellular accumulation of U solids with nanometer sized lath structures that contained U and P. In bicarbonate, however, more phosphate was removed than required to stoichiometrically balance the U(VI)/U(IV) fraction determined by XAFS, suggesting that U(IV) precipitated together with phosphate in this system. When anthraquinone-2,6-disulfonate (AQDS), a known electron shuttle, was added to the experimental reactors, the dominant removal mechanism in both buffers was reduction to a non-uraninite U(IV) phase.Uranium immobilization by abiotic precipitation or microbial reduction has been extensively reported; however, the present work suggests that strain ES6 can remove U(VI) from solution simultaneously through precipitation with phosphate ligands and microbial reduction, depending on the environmental conditions. Cellulomonadaceae are environmentally relevant subsurface bacteria and here, for the first time, the presence of multiple U immobilization mechanisms within one organism is reported using Cellulomonas sp. strain ES6en_US
dc.titleMultiple mechanisms of uranium immobilization by Cellulomonas sp. strain ES6en_US
dc.typeArticleen_US
mus.citation.extentfirstpage264en_US
mus.citation.extentlastpage276en_US
mus.citation.issue2en_US
mus.citation.journaltitleBiotechnology and Bioengineeringen_US
mus.citation.volume108en_US
mus.identifier.categoryChemical & Material Sciencesen_US
mus.identifier.categoryEngineering & Computer Scienceen_US
mus.identifier.categoryLife Sciences & Earth Sciencesen_US
mus.identifier.doi10.1002/bit.22956en_US
mus.relation.collegeCollege of Agricultureen_US
mus.relation.collegeCollege of Engineeringen_US
mus.relation.collegeCollege of Letters & Scienceen_US
mus.relation.departmentCenter for Biofilm Engineering.en_US
mus.relation.departmentChemical & Biological Engineering.en_US
mus.relation.departmentChemical Engineering.en_US
mus.relation.departmentChemistry & Biochemistry.en_US
mus.relation.departmentMicrobiology & Immunology.en_US
mus.relation.universityMontana State University - Bozemanen_US
mus.relation.researchgroupCenter for Biofilm Engineering.en_US
mus.data.thumbpage10en_US


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