Anaerobic Transformation of 2,4,6-Trinitrotoluene and Other Nitroaromatic Compounds

Preuß, Andrea; Rieger, Paul-Gerhard

doi:10.1007/978-1-4757-9447-2_5

Cited by 50 publications

(51 citation statements)

References 42 publications

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“…Oxygen is even more electronegative than the nitrogen atom; hence, the N-O bond is polarized. The partially positive charge of the nitrogen atom, combined with its high electronegativity, makes the nitro group easily reducible (175). Reduction of nitro groups on aromatic rings is widely distributed among living organisms.…”

Section: Chemistry Of Tntmentioning

confidence: 99%

“…seems to proceed via TAT, the mineralization of TNT under anaerobic conditions must involve the elimination of the amino groups from TAT. The biological transformation of TAT is possible only at neutral pH and under anoxic conditions; otherwise the molecule is unstable (175). However, the role of TAT as the key metabolite in the anaerobic metabolism of TNT has been questioned by Hawari et al (103), who suggested that this compound is a dead-end product which prevents mineralization of the nitroaromatic.…”

Section: Vol 65 2001 Metabolism Of Nitroaromatic Compounds 341mentioning

confidence: 99%

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Biological Degradation of 2,4,6-Trinitrotoluene

Esteve‐Núñez

Caballero

Ramos

2001

Microbiol Mol Biol Rev

420

287

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Nitroaromatic compounds are xenobiotics that have found multiple applications in the synthesis of foams, pharmaceuticals, pesticides, and explosives. These compounds are toxic and recalcitrant and are degraded relatively slowly in the environment by microorganisms. 2,4,6-Trinitrotoluene (TNT) is the most widely used nitroaromatic compound. Certain strains of Pseudomonas and fungi can use TNT as a nitrogen source through the removal of nitrogen as nitrite from TNT under aerobic conditions and the further reduction of the released nitrite to ammonium, which is incorporated into carbon skeletons. Phanerochaete chrysosporium and other fungi mineralize TNT under ligninolytic conditions by converting it into reduced TNT intermediates, which are excreted to the external milieu, where they are substrates for ligninolytic enzymes. Most if not all aerobic microorganisms reduce TNT to the corresponding amino derivatives via the formation of nitroso and hydroxylamine intermediates. Condensation of the latter compounds yields highly recalcitrant azoxytetranitrotoluenes. Anaerobic microorganisms can also degrade TNT through different pathways. One pathway, found in Desulfovibrio and Clostridium, involves reduction of TNT to triaminotoluene; subsequent steps are still not known. Some Clostridium species may reduce TNT to hydroxylaminodinitrotoluenes, which are then further metabolized. Another pathway has been described in Pseudomonas sp. strain JLR11 and involves nitrite release and further reduction to ammonium, with almost 85% of the N-TNT incorporated as organic N in the cells. It was recently reported that in this strain TNT can serve as a final electron acceptor in respiratory chains and that the reduction of TNT is coupled to ATP synthesis. In this review we also discuss a number of biotechnological applications of bacteria and fungi, including slurry reactors, composting, and land farming, to remove TNT from polluted soils. These treatments have been designed to achieve mineralization or reduction of TNT and immobilization of its amino derivatives on humic material. These approaches are highly efficient in removing TNT, and increasing amounts of research into the potential usefulness of phytoremediation, rhizophytoremediation, and transgenic plants with bacterial genes for TNT removal are being done

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Section: Chemistry Of Tntmentioning

confidence: 99%

Section: Vol 65 2001 Metabolism Of Nitroaromatic Compounds 341mentioning

confidence: 99%

Biological Degradation of 2,4,6-Trinitrotoluene

Esteve‐Núñez

Caballero

Ramos

2001

Microbiol Mol Biol Rev

420

287

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“…Reduction of aryl nitro groups to corresponding amines has been reported for anaerobic systems (8,10,32,36). C. acetobutylicum transformed TNT with accumulation of the hydroxylamino intermediates, specifically 4-hydroxylamino-2,6-dinitrotoluene (4HA26DNT) and 2,4-dihydroxylamino-6-nitrotoluene (24DHA6NT), without formation of commonly observed amines (8,32,36).…”

mentioning

confidence: 99%

2,4,6-Trinitrotoluene Reduction by an Fe-Only Hydrogenase in Clostridium acetobutylicum

Watrous¹,

Clark

Kutty

et al. 2003

Appl Environ Microbiol

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The role of hydrogenase on the reduction of 2,4,6-trinitrotoluene (TNT) in Clostridium acetobutylicum was evaluated. An Fe-only hydrogenase was isolated and identified by using TNT reduction activity as the selection basis. The formation of hydroxylamino intermediates by the purified enzyme corresponded to expected products for this reaction, and saturation kinetics were determined with a K m of 152 M. Comparisons between the wild type and a mutant strain lacking the region encoding an alternative Fe-Ni hydrogenase determined that Fe-Ni hydrogenase activity did not significantly contribute to TNT reduction. Hydrogenase expression levels were altered in various strains, allowing study of the role of the enzyme in TNT reduction rates. The level of hydrogenase activity in a cell system correlated (R 2 ‫؍‬ 0.89) with the organism's ability to reduce TNT. A strain that overexpressed the hydrogenase activity resulted in maintained TNT reduction during late growth phases, which it is not typically observed in wild type strains. Strains exhibiting underexpression of hydrogenase produced slower TNT rates of reduction correlating with the determined level of expression. The isolated Fe-only hydrogenase is the primary catalyst for reducing TNT nitro substituents to the corresponding hydroxylamines in C. acetobutylicum in whole-cell systems. A mechanism for the reaction is proposed. Due to the prevalence of hydrogenase in soil microbes, this research may enhance the understanding of nitroaromatic compound transformation by common microbial communities.

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“…Further reduction of the remaining two nitro groups by aerobic microorganisms has not been observed (Preuss and Rieger 1995). Reduction of the remaining two nitro groups by anaerobic microorganisms (Stahl and Aust 1995) would result in triaminotoluene, which is unstable in the presence of oxygen because it is susceptible to autooxidation and polymerization (Preuss and Rieger 1995).…”

Section: Biodegradationmentioning

confidence: 99%

“…Degradation of nitroaromatic compounds by plants is possible (Schnoor 1997) A number of investigators have examined the efficacy of microbial degradation as a mechanism for breaking up the nitroaromatic contaminants. Transformation of 2,4,6-TNT, 2,4-DNT, and 2,6-DNT can occur under both aerobic and anaerobic conditions (Preuss and Rieger 1995). Therefore, a wide variety of intermediate degradation products maybe produced, depending on the degradation mechanism.…”

Section: Biodegradationmentioning

confidence: 99%

Supplemental feasibility study for remedial action for the Groundwater Operable Unit at the Chemical Plant Area of the Weldon Spring Site, Weldon Spring, Missouri

1999

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Anaerobic Transformation of 2,4,6-Trinitrotoluene and Other Nitroaromatic Compounds

Cited by 50 publications

References 42 publications

Biological Degradation of 2,4,6-Trinitrotoluene

Biological Degradation of 2,4,6-Trinitrotoluene

2,4,6-Trinitrotoluene Reduction by an Fe-Only Hydrogenase in Clostridium acetobutylicum

Supplemental feasibility study for remedial action for the Groundwater Operable Unit at the Chemical Plant Area of the Weldon Spring Site, Weldon Spring, Missouri

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