Reductive biotransformation as a pretreatment to enhance in situ chemical oxidation of nitroaromatic and nitroheterocyclic explosives

Madeira, Camila L.; Kadoya, Warren M.; Li, Guangbin; Wong, Stanley; Sierra-Álvarez, Reyes; Field, Jim A.

doi:10.1016/j.chemosphere.2019.01.178

Cited by 12 publications

(6 citation statements)

References 44 publications

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“…The experiments included endogenous controls (no ATO addition) and abiotic controls (sterile medium without the inoculum). Mass balances were performed based on the ideal gas law, Henry's law, and acid−base equilibrium, as described by Madeira et al 16 A separate experiment was performed with the enrichment culture series B for the determination of ATO-carbon incorporated into the cells (Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

Microbial Enrichment Culture Responsible for the Complete Oxidative Biodegradation of 3-Amino-1,2,4-triazol-5-one (ATO), the Reduced Daughter Product of the Insensitive Munitions Compound 3-Nitro-1,2,4-triazol-5-one (NTO)

Madeira

Jog

Vanover

et al. 2019

Environ. Sci. Technol.

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3-Nitro-1,2,4-triazol-5-one (NTO) is one of the main ingredients of many insensitive munitions, which are being used as replacements for conventional explosives. As its use becomes widespread, more research is needed to assess its environmental fate. Previous studies have shown that NTO is biologically reduced to 3-amino-1,2,4-triazol-5-one (ATO). However, the final degradation products of ATO are still unknown. We have studied the aerobic degradation of ATO by enrichment cultures derived from the soil. After multiple transfers, ATO degradation was monitored in closed bottles through measurements of inorganic carbon and nitrogen species. The results indicate that the members of the enrichment culture utilize ATO as the sole source of carbon and nitrogen. As ATO was mineralized to CO2, N2, and NH4 +, microbial growth was observed in the culture. Co-substrates addition did not increase the ATO degradation rate. Quantitative polymerase chain reaction analysis revealed that the organisms that enriched using ATO as carbon and nitrogen source were Terrimonas spp., Ramlibacter-related spp., Mesorhizobium spp., Hydrogenophaga spp., Ralstonia spp., Pseudomonas spp., Ectothiorhodospiraceae, and Sphingopyxis. This is the first study to report the complete mineralization of ATO by soil microorganisms, expanding our understanding of natural attenuation and bioremediation of the explosive NTO.

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Section: Methodsmentioning

confidence: 99%

Microbial Enrichment Culture Responsible for the Complete Oxidative Biodegradation of 3-Amino-1,2,4-triazol-5-one (ATO), the Reduced Daughter Product of the Insensitive Munitions Compound 3-Nitro-1,2,4-triazol-5-one (NTO)

Madeira

Jog

Vanover

et al. 2019

Environ. Sci. Technol.

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“…NTO (5-nitro-1,2,4-triazol-3-one), as one of the insensitive munitions, has gained increased interest related to its degradation in environment. , Abiotic photolysis and biotic reduction were suggested to be the main pathways for NTO transformation. There are a few studies of NTO biodegradation in the environment. − Experiments were conducted using microbial communities from a wide range of soils with a variety of electron-donating substrates, such as methanol, ethanol, acetate, pyruvate, lactate, and hydrogen. NTO was found to be first biotransformed through the reduction to 5-(hydroxylamino)-1,2,4-triazol-3-one and subsequently to 5-amino-1,2,4-triazol-3-one (ATO).…”

Section: Introductionmentioning

confidence: 99%

NTO Degradation by Nitroreductase: A DFT Study

2022

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NTO (5-nitro-1,2,4-triazol-3-one), an energetic material used in military applications, may be released to the environment during manufacturing, transportation, storage, training, and disposal. A detailed investigation of the possible mechanism for all steps of reduction of NTO by oxygen-insensitive nitroreductase, as one of the pathways for NTO environmental degradation, was performed by computational study at the PCM(Pauling)/M06-2X/6-311++G(d,p) level. Obtained results reveal an overall sequence for NTO transformation into ATO (5-amino-1,2,4-triazol-3-one) with the flavin mononucleotide (FMN) cofactor of nitroreductase. Reduction of the nitro group to the nitroso group and the nitroso group to the hydroxylamino group follow a similar mechanism that consists of the sequential electron and proton transfer from the flavin cofactor. The hydride transfer mechanism may contribute to reduction of the nitroso group by the anionic form of the reduced flavin cofactor. Reduction of 5-(hydroxylamino)-1,2,4-triazol-3-one by the neutral form of the reduced flavin is impossible, whereas reduction of the hydroxylamino group to the amino group occurs with the anionic form of the reduced cofactor by a mechanism involving an initial proton transfer from the hydroxonium ion followed by two electrons and one proton transfers from the flavin cofactor. Small activation energies and high exothermicity support the significant contribution of oxygen-insensitive nitroreductase and other enzymes, containing FMN as a cofactor, to NTO degradation in the environment.

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“…A coupled reduction-oxidation strategy has been recently found to be a promising approach in achieving mineralization in complex wastewaters for both legacy MCs and new IHEs (Gilbert & Sale, 2005;Hawari et al, 1999;Khatiwada et al, 2018;Madeira et al, 2017Madeira et al, , 2019Rodgers & Bunce, 2000;Shen et al, 2013;M. Sun et al, 2012;Thomas et al, 2008).…”

Section: Background and Motivationmentioning

confidence: 99%

“…It has been recognized that first reducing explosives makes intermediate compounds that are more susceptible to oxidation reactions, and the combined strategy of reduction followed by oxidation in electrochemical systems (Ayoub et al, 2011;Cronin et al, 2007;R. B. Doppalapudi et al, 2003;Madeira et al, 2019;Shen et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Electrochemically-induced in situ degradation of legacy munitions and insensitive high explosives in manufacturing wastewater

Rafei Dehkordi

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Reductive biotransformation as a pretreatment to enhance in situ chemical oxidation of nitroaromatic and nitroheterocyclic explosives

Cited by 12 publications

References 44 publications

Microbial Enrichment Culture Responsible for the Complete Oxidative Biodegradation of 3-Amino-1,2,4-triazol-5-one (ATO), the Reduced Daughter Product of the Insensitive Munitions Compound 3-Nitro-1,2,4-triazol-5-one (NTO)

Microbial Enrichment Culture Responsible for the Complete Oxidative Biodegradation of 3-Amino-1,2,4-triazol-5-one (ATO), the Reduced Daughter Product of the Insensitive Munitions Compound 3-Nitro-1,2,4-triazol-5-one (NTO)

NTO Degradation by Nitroreductase: A DFT Study

Electrochemically-induced in situ degradation of legacy munitions and insensitive high explosives in manufacturing wastewater

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