2.4- /2,6-dinitrotoluene degradation

Suen WC and Spain JC, Cloning and characterization of Pseudomonas sp. strain dinitro-toluene genes for 2,4-dinitrotoluene degradation, J. Bacteriol., 175, 1831, 1993. 

Acetylation of 2-nitro-4-aminotoluene by Mucrosporium sp. was observed in the course of 2,4-dinitrotoluene degradation (31). The isomer 2-acetamido-4-nitrotoluene could not be detected as a transformation product. This indicates that acetylation of an aromatic amino group is affected by its position on the ring. In this case the methyl residue ortho to the amino group could hinder the acetylation of 2-amino-4-nitrotoluene. Since our attempts to synthesize an authentic standard of 2-formamido-4,6-dinitrotoluene have failed so far, we could not investigate a formylation reaction of 2-amino-4,6-nitro-toluene by the fungus. 

Valli K, BJ Brock, DK Joshi, MH Gold (1992a) Degradation of 2,4-dinitrotoluene by the lignin-degrading fungus Phanerochaete chrysosporium. Appl Environ Microbiol 58 221-228. 

Nishino SF, GC Paoli, JC Spain (2000) Aerobic degradation of nitrotoluenes and pathway for bacterial degradation of 2,6-dinitrotoluene. Appl Environ Microbiol 66 2139-2147. 

Razo-Flores et al. (1999) studied the fate of 2,4-dinitrotoluene (120 mg/L) in an upward-flow anaerobic sludge bed reactor containing a mixture of volatile fatty acids and/or glucose as electron donors. 2,4-Dinitrotoluene was transformed to 2,4-diaminotoluene (52% molar yield) in stoichiometric amounts until day 125. Thereafter, the amine underwent continued degradation. Approximately 98.5% of the volatile fatty acids in the reactor was converted to methane during the 202-d experiment. 

Haidour and Ramos (1996) analyzed the degradation products of 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene by the bacterium Pseudomonas sp. clone A under aerobic conditions utilizing 2,4-dinitrotoluene as a source of nitrogen. Two metabolites tentatively identified were 2-amino-4-nitrotoluene and 4-amino-2-nitrotoluene. Also, three azoxytoluenes were identified 4,4 -dinitro-2,2 -azoxytoluene, 2,2 -dinitro-4,4 -azoxytoluene, and 2,4 -dinitro-2, 4-azoxytoluene. 2-Amino-4-nitrotoluene and 4-amino-2-nitrotoluene were also identified as products of 2,4-dinitrotoluene metabolism by Clostridium acetobutylicum via the hydroxyl-aminonitrotoluene intermediates, namely 4-hydroxylamino-2-nitrotoluene and 2-hydroxylamino-4-nitrotoluene (Hughes et al., 1999). 

Photolytic. Low et al. (1991) reported that nitro-containing compounds (e.g., 2,4-dinitrophenol) degrade via UV light in the presence of titanium dioxide yielding ammonium, carbonate, and nitrate ions. By analogy, 2,4-dinitrotoluene should degrade forming identical ions. 

Biological. When 2,6-dinitrotoluene was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, significant biodegradation with gradual acclimation was followed by deadaptive process in subsequent subcultures. At a concentration of 5 mg/L, 82, 55, 47, and 29% losses were observed after 7, 14, 21, and 28-d incubation periods, respectively. At a concentration of 10 mg/L, only 57, 49, 35, and 13% were observed after 7, 14, 21, and 28-d incubation periods, respectively (Tabak et al., 1981). Under anaerobic and aerobic conditions, a sewage inoculum degraded 2,6-dinitrotoluene to aminonitrotoluene (Hallas and Alexander, 1983). 

During World War II, copious quantities of ordnance were lost into the harbor at Halifax, Nova Scotia. Decades later, these UUXO now present a significant environmental contamination problem. Studies conducted on this ordnance by Sandia National Laboratories [1] suggest that there may be sufficient concentrations of explosive chemical signature compounds emanating from UUXO to enable detection with chemical sensors. Some UUXO in Halifax Harbor have been shown to produce parts-per-billion levels of explosives in the water near the ordnance. In addition to the parent explosive compound (TNT), other explosive-related compounds such as 2,4-dinitrotoluene (2,4-DNT) were detected, as were degradation products of TNT such as 4-amino-2,6-dinitrotoluene (4-ADNT), and... 

C. bifermentam strain CYS-1 was also isolated from our anaerobic bioreactor. Shin Crawford (1995) examined the ability of CYS-1 to degrade TNT cometabolically in various defined media. This strain could overcome the toxicity of and degrade >150 ppm TNT in liquid media supplemented with a rich cosubstrate such as yeast extract or trypticase soy, given an appropriate inoculum ( 107 CFU/ml). Furthermore, it was found that CYS-1 could degrade TNT which contaminated a sandy loam soil. The degradation of TNT proceeded through the transient intermediates 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. 

Various modern products may serve as sources for trace amounts of PAA. The origins, known hazards, release restrictions and environmental fate of PAA derived from azo dyes have been reviewed2. The metabolism of nitroarenes is closely linked to that of aromatic amines, as shown in a simplified way in equation 369. Gloeophyllum trabeum cultures spiked with TNT show formation of nitroaromatic amines such as 2-ami no-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. Also, autoxi-dation of the methyl group of TNT or its metabolites may take part in the degradation process, as shown by the presence of Schiff bases and oligomeric and polymeric species detection and determination of the analytes after LLE and concentration were by HPLC-UVD or GC-MS70. 

Simultaneous degradation of 2,4- and 2,6-dinitrotoluene has been achieved in a fluidized-bed biofilm reactor (Lendemann et al. 1998), and was successfully operated with contaminated ground-water containing 2- and 4-nitrotoluenes and 2,4- and 2,6-dinitro-toluenes. Nitrite formed during degradation was accounted for as nitrate. 

Trinitrotoluene (TNT) is the most commonly used energetic compound and found in the soils at U.S. Army installations [16,17], Military grades of TNT contain up to 8% DNTs (2,4-dinitrotoluene and 2,6-dinitrotoluene) as manufacturing impurities, and TNT is often degraded to DNT in hydric soils (i.e., wet anaerobic environments) [18,19], Other compounds are also generated when TNT is degraded (e.g., 2-amino-4,6-dinitrotoluene [2-ADNT], 4-amino-2,6-dinitrotoluene [4-ADNT], 1,3,5-trinitrobenzene [TNB], and others). Contamination from TNT, DNTs, and their environmental breakdown products is known to persist in soil for years [20],... 

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