Aerobic Denitration of 2,4,6-Trinitrotoluene in the Presence of Phenazine Compounds and Reduced Pyridine Nucleotides
(2012) Environmental Science & Technology (Washington) — Vol. 46, n° 19, p. 10605-10613 (2012)
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Agathos, Spiros N. 
- Abstract
- Phenazine-containing spent culture supernatants of Pseudomonas aeruginosa concentrated with a C 18 solid-phase extraction cartridge initiate NAD(P)H-dependent denitration of 2,4,6-trinitrotoluene (TNT). In this study, TNT denitration was investigated under aerobic conditions using two phenazine secondary metabolites excreted by P. aeruginosa, pyocyanin (Py) and its precursor phenazine-1-carboxylic acid (PCA), and two chemically synthesized pyocyanin analogs, phenazine methosulfate (PMS +) and phenazine ethosulfate (PES +). The biomimetic Py/NAD(P)H/O 2 system was characterized and found to extensively denitrate TNT in unbuffered aqueous solution with minor production of toxic aminoaromatic derivatives. To a much lesser extent, TNT denitration was also observed with PMS + and PES + in the presence of NAD(P)H. No TNT denitration was detected with the biomimetic PCA/NAD(P)H/O 2 system. Electron paramagnetic resonance (EPR) spectroscopy analysis of the biomimetic Py/NAD(P)H/O 2 system revealed the generation of superoxide radical anions (O 2 ·-). In vitro TNT degradation experiments in the presence of specific inhibitors of reactive oxygen species suggest a nucleophilic attack of superoxide radical anion followed by TNT denitration through an as yet unknown mechanism. The results of this research confirm the high functional versatility of the redox-active metabolite pyocyanin and the susceptibility of aromatic compounds bearing electron-withdrawing substituents, such as nitro groups, to superoxide-driven nucleophilic attack. © 2012 American Chemical Society.
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Stenuit, B., Lamblin, G., Cornelis, P., & Agathos, S. N. (2012). Aerobic Denitration of 2,4,6-Trinitrotoluene in the Presence of Phenazine Compounds and Reduced Pyridine Nucleotides. Environmental Science & Technology (Washington), 46(19), 10605-10613. https://doi.org/10.1021/es302046h (Original work published 2012)