Enhanced U(VI) release from autunite mineral by aerobic Arthrobacter sp. in the presence of aqueous bicarbonate

Journal Article · Fri Apr 20 04:00:00 EDT 2012 · Chemical Geology

DOI:https://doi.org/10.1016/j.chemgeo.2012.03.010· OSTI ID:1038634

Katsenovich, Yelena; Carvajal, Denny A; Wellman, Dawn M; Lagos, Leonel

The bacterial effect on U(VI) leaching from the autunite mineral (Ca[(UO{sub 2})(PO{sub 4})]{sub 2} {center_dot} 3H{sub 2}O) was investigated to provide a more comprehensive understanding into important microbiological processes affecting autunite stability within subsurface bicarbonate-bearing environments. Experiments were performed in a culture of G975 Arthrobacter oxydans strain, herein referred to as G975, a soil bacterium previously isolated from Hanford Site soil. 91 mg of autunite powder and 50 mL of phosphorus-limiting sterile media were amended with bicarbonate ranging between 1-10 mM in glass reactor bottles and inoculated with G975 strain after the dissolution of autunite was at steady state. SEM observations indicated G975 formed a biofilm on the autunite surface and penetrated the mineral cleavages. The mineral surface colonization by bacteria tended to increase concomitantly with bicarbonate concentrations. Additionally, a sterile cultureware with inserts was used in non-contact bioleaching experiments where autunite and bacteria cells were kept separately. The data suggest the G975 bacteria is able to enhance U(VI) leaching from autunite without the direct contact with the mineral. In the presence of bicarbonate, the damage to bacterial cells caused by U(VI) toxicity was reduced, yielding similar values for total organic carbon (TOC) degradation and cell density compared to U(VI)-free controls. The presence of active bacterial cells greatly enhanced the U(VI) bioleaching from autunite in bicarbonate-amended media.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1038634
• Report Number(s): PNNL-SA-83650; EY4049110
• Journal Information: Chemical Geology, Journal Name: Chemical Geology Vol. 308-309; ISSN CHGEAD; ISSN 0009-2541
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACID CARBONATES
AUTUNITE
Arthrobacter sp
BACTERIA
CARBON
DISSOLUTION
GLASS
LEACHING
SOILS
STABILITY
STRAINS
TOXICITY
aqueous bicarbonate
microscopy
radionuclides
toxicity