• KSBB Journal
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• v.14 no.3
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• pp.315-321
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• 1999

The relationships between the explosive 2,4,6-trinitrotoluene (TNT) degradation by Stenotrophomonas maltophilia and several relevant physicochemical environmental parameters were examined. At neutral pH of the cultures, the degradation of TNT proceeded to completion, whereas only about 50% of TNT was utilized when the cultures were adjusted to acidic pH. The effect of various co-substrates (e.g., glucose, fructose, acetate, citrate, succinate) on the degradation of TNT by the test culture of S. maltophilia was evaluated. The results indicated that, among the various co-substrates studies, the test culture that received 2 mM fructose degraded 100 mg/L of TNT completely within 20 days of incubation at ambient temperature, whereas partial degradation of TNT was observed in the test culture with acetate, citrate, or succinate as a co-substrate, respectively. In fact, fructose was the best co-substrate for TNT degradation in this experiment. The effect of supplemented nitrogens [e.g., (NH$_4$)$_2$,SO$_4$, NH$_4$Cl. urea] on the TNT degradation was monitored. All supplemented nitrogens in this study were inhibitory to TNT degradation. Addition of 1% Tween80 accelerated TNT degradation, and showed complete degradation of TNT within 8 days of incubation. Addition of yeast extract resulted higher growth yields, based on turbidity measurement, but it inhibited TNT degradation.

• Journal of Korean Society on Water Environment
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• v.20 no.1
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• pp.32-36
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• 2004

In this study, uptake and translocation of 2,4,6-trinitrotoluene(TNT) by plant in a hydroponic culture was quantified with two indigenous plant species, Aeschynomene indica and Abutilon avicennae on various initial concentrations of TNT ranging from 20 to 80 mgTNT/L. Experiments were sterilized to exclude the activity of microorganisms and conducted in duplicate. Weight loss of two plant species in added TNT culture media was higher than in control. At over 2OmgTNTIL, there appeared to be phytotoxicity from TNT as indicated by severe yellow-chlorosis and increase of falling leaves. TNT removal rate normalized(K) to the plant fresh weight of Abutilon avicennae and Aeschynomene indica was that the higher TNT concentrations resulted in lower TNT removal rate normalized(K) to the plant fresh weight. Approximately 96% of the TNT in viable microflora-hydroponic culture was removed after 96h of the experiments.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.250-250
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• 2002

This study confirmed that white rot fungus Irpex lacteus was able to metabolize 2,4,6-trinitrotoluene (TNT) with two different initial transformations. In one metabolic pathway of TNT a nitro group was removed from the aromatic ring of TNT. Hydride-Meisenheimer complexes of TNT (H/sup -/-TNT), colored dark redo were confirmed as the intermediate in this transformation by comparison with the synthetic compounds. 2,4-Dinitrotoluene as a following metabolic product was detected, and nitrite produced by denitration of $H^-$-TNT supported this transformation. In the other TNT pathway, nitro groups in TNT were successively reduced to amino groups via hydroxylamines. Hydroxylamino-dinitrotoluenes and amino-dinitrotoluenes were identified as the intermediates. The activity of a membrane-associated aromatic nitroreductase was detected in the cell-free extract of I. lacteus. This enzyme catalyzed the nitro group reduction of TNT with NADPH as a cofactor, Enzyme activity was not observed in the presence of molecular oxygen.

• Journal of Microbiology
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• v.38 no.4
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• pp.250-254
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• 2000

This study confirmed that white rot fungus Irpex lacteus was able to metabolize 2,4,6-trinitrotoluene (TNT) with two different initial transformations. In one metabolic pathway of TNT a nitro group was removed from the aromatic ring of TNT. Hydride-Meisenheimer complexes of TNT (H$\^$-/-TNT), colored dark redo were confirmed as the intermediate in this transformation by comparison with the synthetic compounds. 2,4-Dinitrotoluene as a following metabolic product was detected, and nitrite produced by denitration of H$\^$-/-TNT supported this transformation. In the other TNT pathway, nitro groups in TNT were successively reduced to amino groups via hydroxylamines. Hydroxylamino-dinitrotoluenes and amino-dinitrotoluenes were identified as the intermediates. The activity of a membrane-associated aromatic nitroreductase was detected in the cell-free extract of I. lacteus. This enzyme catalyzed the nitro group reduction of TNT with NADPH as a cofactor, Enzyme activity was not observed in the presence of molecular oxygen.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.2
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• pp.105-111
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• 2002

The biological removal of 2,4,6-trinitrotoluene (TNT) was studied in a bench-scale bioreactor using a bacterial culture of strain OK-5 originally Isolated from soil samples contaminated with TNT. The TNT was completely removed within 4 days of incubation in a 2.5 L bench-scale bioreactor containing a newly developed medium. The TNT was catabolized in the presence of different supplemented carbons. Only minimal growth was observed in the killed controls and cultures that only received TNT during the incubation period. This catabolism was affected by the concentration ratio of the substrate to the biomass. The addition of various nitrogen sources produced a delayed effect for the TNT degradation. Tween 80 enhanced the degradation of TNT under these conditions. Two metabolic intermediates were detected and identified as 2-amino-4, 6-dinitrotoluene and 4-amino-2, 6-dinitrotoluene based on HPLC and GC-MS analyses, respectively. Strain OK-5 was characterized using the BIOLOG system and fatty acid profile produced by a microbial identification system equipped with a Hewlett Packard HP 5890 II gas chromatograph. As such, the bacterium was identified as a Stenotrophomonas species and designated as Stenotrophomonas sp. OK-5.

• Clean Technology
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• v.27 no.3
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• pp.247-254
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• 2021

In this study, an eco-friendly combustion process of waste 2,4,6-trinitrotoluene (TNT: 2,4,6-trinitrotoluene) was developed, and fundamental data for the quantity of the organic matter in the final combustion residues is presented. Because complete combustion of TNT is not possible theoretically, the combustion process was optimized to reduce organic matter content in the combustion residue by performing measures such as heating time changes, addition of propellant material, and after treatment using a high-temp electrical furnace. From the results, it was confirmed that the organic matter content in the residue could be decreased to 7 ~ 10% with each method. The quantity of the organic matter could be minimized by optimizing the combustion conditions of the process. With only a combustion time increase, the amount of organic matter in the combustion residues was measured at about 9 wt%. The environmental friendliness of the final exhaust gas was also confirmed by real time gas component analyses. In addition, the organic contents could be reduced by a further 2 wt% by applying an additional heat treatment using an external electric furnace after the first incineration treatment. In the combustion process of propellant added waste TNT, it was found that various TNT wastes could be treated using the same eco-friendly protocols because the organic content in the residue decreased in accordance with the amount of propellant. The amount of the organic matter content produced by all these methods fulfilled the requirements under the Waste Management Act.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.46-54
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• 2015

Toxicity and uptake of 2,4,6-trinitrotoluene (TNT) in three different soils (OECD soil, natural soil and loess) to earthworm (Eisenia fetida) were investigated at several different spiked concentrations of TNT (0 to 200 mg/kg for OECD and natural soils, and 0 to 35 mg/kg for loess) and for different exposure periods (7, 14, 21, and 28 d). The LC₅₀ values for 7 d exposure were 160.1, 159.4, and 28.81 mg/kg for OECD soil, natural soil, and loess, respectively. The LC₅₀ values for 14, 21, and 28 d exposure were almost the same as those for 7 d exposure, showing that 7 d exposure time was enough to decide the toxicity (LC₅₀) of TNT to Eisenia fetida, because the highest concentration of TNT in earthworm body was observed within around 5 d. The LC₅₀ and uptake of TNT in loess were higher than those in OECD and natural soil. The uptake of TNT to the earthworm were correlated well with the initial concentration of TNT in the soil and TNT porewater concentration (R²> 0.9 in OECD, natural, and loess). The concentration of TNT in earthworm body decreased after 5 d, possibly caused by natural degradation of TNT by soil bacteria as well as earthworm.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.04a
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• pp.62-63
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• 1999

Reduction 2,4,6-Trinitrotoluene by zero valent iron was studied in a batch reactor under anoxic conditions. Results showed that the removal of TNT was a pseudo-first order and the rate was dependent on the available metal surface area. Final product, presumably triaminotoluene, accumulated in the solution as well as on the metal surface. However, little amounts of aminodinitrotoluenes were detected. Therefore, it is postulated that the reduction of nitro group occurs simultaneously in all three position.

• Journal of Soil and Groundwater Environment
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• v.23 no.6
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• pp.46-53
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• 2018

Mobility reduction of 2,4,6-trinitrotoluene (TNT) was tested by amending monopotassium phosphate (MKP) and montmorillonite to a firing range soil contaminated with TNT. While addition of MKP enhanced sorption of TNT on soil matrix, and combined use of MKP with montmorillonite significantly decreased desorption of TNT as well as remarkably increased the TNT sorption. Montmorillonite amendment by 5% of soil mass resulted in TNT desorption of 0.12 mg/kg from soil loaded with 9.93 mg/kg-TNT. The decrease of TNT desorption was proportional to the amount of montmorillonite amended. At 10 and 15% amendment, only 0.79 and 1.23 mg/kg-TNT was desorbed from 29.33 and 48.80 mg/kg-TNT. In addition, the leaching of TNT with synthetic precipitation leaching procedure (SPLP) and hydroxypropyl-${\beta}$-cyclodextrin (HPCD) decreased, indicating that TNT in MKP/montmorillonite-treated soil became more stable and less leachable. The results demonstrate that addition of MKP and montmorillonite to TNT-contaminated soil reduces the mobility of TNT from soil not only by increasing TNT sorption, but also decreasing TNT desorption. It was found that MKP and montmorillonite amendments by 5 and 10% of soil mass, respectively, were optimal for reducing the mobility of soil TNT.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.38-41
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• 2001

It has been reported that some plants have the potential to metabolize the 2,4,6-trintroluene (TNT) in contaminated soils, sediments and natural water. In this study, the effects of TNT on germination and early seedling development of Abutilion avicennae was characterized in a germination test. Concentration up to 80 mg/L TNT did not affect germination but root and shoot growth, and fresh biomass decreased as TNT concentration increased. A series of axenic hydroponical batch culture of Abutilion avicennae at various initial TNT concentration was used to determine its transformation kinetics, to identify products formed, and to evaluate phytotoxic effects on the TNT transformation process. At higher initial TNT concentrations, TNT removal rate constant decreased, however, total amount of TNT removed was increased in the culture media. Reductive transformation products of TNT were not detected in the plant culture media but higher concentrations of reduced metabolites were detected in the root and stem extracts of plant material at the 7 days of batch incubation. From these results we concluded that Abutilion avicennae has an intrinsic capacity for taking up and transforming TNT.