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BIOTRANSFORMATION OF 2,4,6-TRINITROTOLUENE (TNT) BY A PLANT-ASSOCIATED FUNGUS FUSARIUM OXYSPORUM
Citation:
Hoehamer, C. F. AND N L. Wolfe. BIOTRANSFORMATION OF 2,4,6-TRINITROTOLUENE (TNT) BY A PLANT-ASSOCIATED FUNGUS FUSARIUM OXYSPORUM. Presented at 22nd Annual Society of Environmental Toxicology and Chemistry Meeting, Baltimore, MD, November 11-15, 2001.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
The capability of a plant-associated fungus, Fusarium oxyvorum, to transform TNT in liquid cultures was investigated. TNT was transformed into 2-amino-4, 6-dinitrotoluene (2-A-DNT), 4-amino-2, 6-dinitrotoluene (4-A- DNT), and 2, 4-diamino-6-nitrotoluene (2, 4-DAT) via 2- and 4-hydroxylamino-dinitrotoluene derivatives, which could be detected as intermediate metabolites. Transformation of TNT, 2-A- DNT, and 4-A-DN'T was observed in whole cultures, as well as with the mycelium alone. Protein extracts were prepared from this fungus, and the concentrated cell-free extracellular culture medium was not capable of transforming TNT; however, low levels of TNT transformation were observed by a membrane fraction in the presence of NADPH under an argon atmosphere. A concentrated extract of soluble enzymes also transformed TNT, but to a lesser extent, under the same conditions. When TNT toxicity was studied with this fungus, a 50 % decrease in the growth of F. oxysporum mycelium was observed when exposed to 20 mg/l TNT.