Oxygenase-Catalyzed Biodegradation of Emerging Water Contaminants:
1,4-Dioxane and N-Nitrosodimethylamine
This research examines the biodegradation of the emerging water
contaminants 1,4-dioxane and N-nitrosodimethylamine (NDMA). Both
1,4-dioxane and NDMA are probable human carcinogens and confirmed
animal carcinogens. Neither is significantly attenuated in the environment
by volatilization or sorption processes. Due to its widespread use
as a solvent stabilizer, 1,4-dioxane is frequently found comingled
with chlorinated solvents at DoD and DoE sites; while NDMA is found
as a degradation byproduct in proximity to aerospace facilities
that used hydrazine-based rocket fuel.
Although the carcinogenic threats of 1,4-dioxane and NDMA have
been understood for many years, they have not historically been
considered important water quality issues, mostly due to lack of
awareness about their potential occurrence in drinking water supplies.
However, with recent advances in analytical methods and growing
public awareness of their occurrence in drinking water supplies,
1,4-dioxane and NDMA are emerging as important water contaminants.
Consequently, a better understanding of the effects of bacterial
degradation on the fate and persistence of 1,4-dioxane and NDMA
in the environment is needed.
This study will identify organisms, and more importantly a class
of enzymes, capable of aerobically biodegrading 1,4-dioxane and
NDMA. Furthermore, this study will elucidate the biochemical pathways
responsible for 1,4-dioxane and NDMA degradation, quantify reaction
kinetics, and develop models to predict those kinetics. It will
also explore the effects of co-contaminants (e.g. 1,1,1-TCA, DCE,
toluene, and chloroform) and inducing substrates (e.g., methane,
propane, butane) on the contaminant degradation rates.
The results of this study will provide a mechanistic understanding
of degradation of 1,4-dioxane and NDMA by aerobic microorganisms
and as such it will provide a foundation for the bioremediation
of these contaminants in natural and engineered systems.
Funded by the Strategic Environmental Research and Development
Program.
Mass spectrometry for dioxane biodegradation pathway
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Biodegradation of the Flame Retardants Polybrominated Diphenyl Ethers
Oxygenase-Catalyzed Biodegradation of Emerging
Water Contaminants: 1,4-Dioxane and N-Nitrosodimethylamine
Characterizing and Evolving the Propane Monooxygenase for N-Nitrosodimethylamine Biodegradation and Green Chemistry
Quantifying Gene Expression to Predict and Optimize Reductive Dechlorination by Dehalococcoides spp.
Application of Microarrays to Identify Biomarkers of Reductive Dehalogenating-Microbial Communities
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