The ability of the white rot fungus Phanerochaete chrysosporium to mineralize 2,4,6-trinitrotoluene (TNT) was studied in the concentration range of 0.36 to 20.36 mg/liter. The initial rate of 14CO2 formation was 30%Yo in 4 days at 0.36 mg of [14C]TNT per liter and decreased to 5% in 4 days at 20.36 mg of [14C]TNT per liter. Such a pronounced inhibition was not observed when a mixture of [14C]2-amino-4,6-dinitrotoluene and

Within a screening program, 91 fungal strains belonging to 32 genera of different ecological and taxonomic groups (wood- and litter-decaying basidiomycetes, saprophytic micromycetes) were tested for their ability to metabolize and mineralize 2,4,6-trinitrotoluene (TNT). All these strains metabolized TNT rapidly by forming monoaminodinitrotoluenes (AmDNT). Micromycetes produced higher amounts of AmDNT than did wood- and litter-decaying basidiomycetes. A significant mineralization of [14C]TNT was only observed for certain wood- and litter-decaying basidiomycetes. The most active strains, Clitocybula dusenii TMb12 and Stropharia rugosa-annulata DSM11372 mineralized 42% and 36% respectively of the initial added [14C]TNT (100 microM corresponding to 4.75 microCi/l) to 14CO2 within 64 days. Micromycetes (deuteromycetes, ascomycetes, zygomycetes) proved to be unable to mineralize [14C]TNT significantly.

that it is possible to run a lignocellulose feedstock biorefi nery with a capacity of about 400 000 t/a wood in an economically and environmentally sound way. A conceptual design of a pilot plant was generated. Its realization and operation will become part of a follow-up project proposal.

No abstract

This work presents laccase-mediated model reactions for coupling of reduced 2,4,6-trinitrotoluene (TNT) metabolites to an organic soil matrix. The structure of an isolated coupling product of 2,4-diamino-6-nitrotoluene (2,4-DANT) to guaiacol as humic constituent was determined. Among several structures, the compound was identified conclusively to be the trinuclear coupling product 5-(2-amino-3-methyl-4-nitroanilino)-3,3dimethoxy-4,4-diphenoquinone. The compound has a weight of 409 g mol ؊1 and may serve as a model reaction for the biogenic formation of bound residues in soil from TNT by coupling aminotoluenes (reduced TNT metabolites) to humic constituents. A linear correlation of the substrate consumption to the enzyme activity was detected. Based on this observation, the described reaction of 2,4-DANT coupling to guaiacol may be used for determination of laccase activity since the reaction was not inhibited by other compounds of culture supernatants. We propose a two-step mechanism for the coupling reaction because 2,4-DANT was not transformed by laccases in the absence of guaiacol and guaiacol oxidation was independent of the presence of 2,4-DANT. The first reaction step is a laccase-mediated dimerization of two guaiacol monomers with subsequent oxidation to a diphenoquinone. The second step is the nucleophilic addition of 2,4-DANT to the ortho position of the carbonyl group of the diphenoquinone structure.