Mechanism of xanthine oxidase catalyzed biotransformation of HMX under anaerobic conditions

Bhushan, Bharat; Paquet, Louise; Halasz, Annamaria; Spain, Jim C.; Hawari, Jalal

doi:10.1016/s0006-291x(03)01001-5

Cited by 41 publications

(23 citation statements)

References 26 publications

(51 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Samples (50 l) were injected into a Supelcosil LC-CN column (4.6 mm [inside diameter] by 25 cm) (Supelco, Oakville, Ontario, Canada), and the analytes were eluted with an isocratic mobile phase of 70% methanol in water at a flow rate of 1.0 ml/min. Nitrite (NO 2 Ϫ ), nitrous oxide (N 2 O), and formaldehyde (HCHO) were analyzed by previously reported methods (3)(4)(5).…”

Section: Methodsmentioning

confidence: 99%

“…In a previous study with diaphorase (a FMN-containing flavoenzyme from Clostridium kluyveri), an oxygen-sensitive one-electron transfer reaction that caused the N denitration of RDX, leading to its decomposition, was reported (3). However, a xanthine oxidase catalyzed an oxygen-sensitive, initial single N denitration of HMX at the FAD site, leading to the spontaneous decomposition of the molecule (5).…”

Section: Isolation and Identification Of Cl-20-degrading Strain Fa1mentioning

confidence: 99%

See 1 more Smart Citation

Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

Bhushan

Paquet

Spain

et al. 2003

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

2, 4,6,8,10,4,6,8,10, is a high-energy polycyclic nitramine compound (17) with a rigid caged structure (Fig. 1). Due to its high energy content and superior explosive properties, it may replace conventionally used explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in the future. The environmental, biological, and health impacts of this energetic chemical and its metabolic products are not known. The severe environmental contamination and biological toxicity of the widely used monocyclic nitramine explosives RDX and HMX are already well documented (11,13,16,22). It is likely that due to its structural similarity with RDX and HMX, CL-20 may also pose a serious threat to the environment by contaminating soils, sediments, and groundwater. Therefore, the microbial degradation of CL-20 should be studied under in vitro and in vivo conditions in order to determine the reaction products and to gain insights into the mechanisms involved in its degradation.Previous reports on the biodegradation and biotransformation of RDX and HMX by a variety of microorganisms (aerobic, anaerobic, and facultative anaerobes) and enzymes have shown that initial N denitration can lead to ring cleavage and decomposition (3, 5-6, 9, 12-15, 21, 26). In a recent study, Trott et al. (24) reported the aerobic biodegradation of CL-20 by the soil isolate Agrobacterium sp. strain JS71. The isolate utilized CL-20 as the sole nitrogen source and assimilated 3 mol of nitrogen per mol of CL-20. However, no information was provided about the mechanism of CL-20 biodegradation.In the present study, a denitrifying Pseudomonas sp. strain, FA1, that utilized CL-20 as a sole nitrogen source was isolated from a garden soil sample. The CL-20 biotransformation conditions were optimized in aqueous medium. The nature and function of the enzyme(s) responsible for the biotransformation of CL-20 by strain FA1 were studied. Stoichiometries of the products formed during the biotransformation of CL-20 by the membrane-associated enzyme(s) from Pseudomonas sp. strain FA1 were determined, and an initial enzymatic N denitration reaction mechanism is proposed. MATERIALS AND METHODSChemicals. CL-20 in ε form and at 99.3% purity was provided by ATK Thiokol Propulsion, Brigham City, Utah. NADH, NADPH, diphenyliodonium chloride (DPI), flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), NaNO 2 , dicumarol, 2,2-dipyridyl, 2-methyl-1,2-di-3-pyridyl-1-propanone (metyrapone), and phenylmethanesulfonyl fluoride were purchased from Sigma Chemicals, Oakville, Ontario, Canada.Nitrous oxide (N 2 O) was purchased from Scott specialty gases, Sarnia, Ontario, Canada. Carbon monoxide (CO) was purchased from Aldrich Chemical Company, Milwaukee, Wis. All other chemicals were of the highest purity available.Isolation and identification of the CL-20-degrading strain. One gram of garden soil was suspended in 20 ml of minimal medium (ingredients per liter of deionized water: K 2 HPO 4 , 1.22 g; KH 2 PO 4 , 0.61 g; N...

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Isolation and Identification Of Cl-20-degrading Strain Fa1mentioning

confidence: 99%

Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

Bhushan

Paquet

Spain

et al. 2003

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Previous reports of biotransformation and biodegradation of RDX and HMX by a variety of microorganisms and enzymes have shown that initial N denitration led to ring cleavage and decomposition (2,3,5,10,14,28). Trott et al (31) reported aerobic biodegradation of CL-20 by the soil isolate Agrobacterium sp.…”

mentioning

confidence: 99%

“…The CL-20 concentration was quantified with an HPLC apparatus connected to a photodiode array detector ( 230 ) as described previously (4). Nitrous oxide (N 2 O) and formaldehyde (HCHO) were analyzed as previously reported (2,3,18). Ammonium cations were analyzed by an SP 8100 HPLC system equipped with a Waters 431 conductivity detector and a Hamilton PRP-X200 (250 mm by 4.6 mm by 10 m) analytical column as described previously (17).…”

mentioning

confidence: 99%

Initial Reaction(s) in Biotransformation of CL-20 Is Catalyzed by Salicylate 1-Monooxygenase from Pseudomonas sp. Strain ATCC 29352

Bhushan

Halasz

Spain

et al. 2004

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

“…Aliquots of the aqueous phase of the reaction mixtures were filtered through 0.45 mm filters (Millipore) prior to analyzing RDX, intermediates and final products. The nitroso derivatives MNX, DNX, and TNX and the ring cleavage products methylenedinitramine (MEDINA) and 4-nitro-2,4-diazabutanal (NDAB) were analyzed as previously described (Hawari et al, 2002;Bhushan et al, 2003). Formaldehyde (HCHO), formic acid (HCOOH), ammonium (NH 4 þ ), nitrate (NO 3 À ), nitrite (NO 2 À ) were analyzed as described by Monteil-Rivera et al (2005).…”

Section: Chemical Analysismentioning

confidence: 99%

Dynamic and equilibrium studies of the RDX removal from soil using CMC-coated zerovalent iron nanoparticles

Naja

Apiratikul

Pavasant

et al. 2009

Environmental Pollution

Self Cite

View full text Add to dashboard Cite

RDX chemical degradation in a contaminated soil was conducted using coated zerovalent iron nanoparticles in both batchRapid chemical degradation of toxic RDX explosive in soil can be accomplished using zerovalent nanoiron suspension stabilized in dilute carboxymethyl cellulose solution (CMC-ZVINs). The effect of operating conditions (redox-potential, Fe/RDX molar ratio) was studied on batchwise removal of RDX in contaminated soil. While anaerobic conditions resulted in 98% RDX removal in 3 h, only slightly over 60% RDX removal could be attained under aerobic conditions. The molar ratio did not have any influence on the intermediate and final RDX degradation products (methylenedinitramine, nitroso derivative, N 2 ,N 2 O, NO 2 À ), however, their distribution changed. Dynamic studies were conducted using a flow-through short column packed with RDX-contaminated soil and fed with CMC-ZVINs. The column was operated at two interstitial velocities (2.2 and 1.6 cm min À1 ), resulting in the 76.6% and 95% removal of the initial RDX soil contamination load (60 mg kg À1 ), respectively. While the column operating conditions could be further optimized, 95% of the RDX initially present in the contaminated soil packed in the column was degraded when flushed with a CMC-ZVINs suspension in this work.

show abstract

Mechanism of xanthine oxidase catalyzed biotransformation of HMX under anaerobic conditions

Cited by 41 publications

References 26 publications

Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

Initial Reaction(s) in Biotransformation of CL-20 Is Catalyzed by Salicylate 1-Monooxygenase from Pseudomonas sp. Strain ATCC 29352

Dynamic and equilibrium studies of the RDX removal from soil using CMC-coated zerovalent iron nanoparticles

Contact Info

Product

Resources

About