Final Report: Molecular mechanisms and kinetics of microbial anaerobic nitrate-dependent U(IV) and Fe(II) oxidation

O'Day, Peggy A.¹  Asta, Maria P.¹  Kanematsu, Masakazu¹  Beller, Harry²  Zhou, Peng²  Steefel, Carl² 

[1] Univ. of California, Merced, CA (United States);Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

关键词: Uranium;    anaerobic oxidation;    kinetics;    reactive transport modeling;    X-ray absorption spectroscopy;    Thiobacillus denitrificans;   

DOI  :  10.2172/1171384
RP-ID  :  DOE-UCM--BioU
PID  :  OSTI ID: 1171384

学科分类：环境科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

In this project, we combined molecular genetic, spectroscopic, and microscopic techniques with kinetic and reactive transport studies to describe and quantify biotic and abiotic mechanisms underlying anaerobic, nitrate-dependent U(IV) and Fe(II) oxidation, which influences the long-term efficacy of in situ reductive immobilization of uranium at DOE sites. In these studies, Thiobacillus denitrificans, an autotrophic bacterium that catalyzes anaerobic U(IV) and Fe(II) oxidation, was used to examine coupled oxidation-reduction processes under either biotic (enzymatic) or abiotic conditions in batch and column experiments with biogenically produced UIVO2(s). Synthesis and quantitative analysis of coupled chemical and transport processes were done with the reactive transport modeling code Crunchflow. Research focused on identifying the primary redox proteins that catalyze metal oxidation, environmental factors that influence protein expression, and molecular-scale geochemical factors that control the rates of biotic and abiotic oxidation.