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Gewählte Publikation:

Nyanhongo, GS; Couto, SR; Guebitz, GM.
(2006): Coupling of 2,4,6-trinitrotoluene (TNT) metabolites onto humic monomers by a new laccase from Trametes modesta.
Chemosphere. 2006; 64(3):359-370 FullText FullText_BOKU

Abstract:
During degradation of trinitrotoluene (TNT) by Trametes modesta, addition of humic monomers prevented the accumulation of all major stable TNT metabolites (aminodinitrotoluenes [AMDNT]) by at least 92% in the presence of 200 mM ferulic acid and guaiacol. Acute toxicity tests with individual TNT metabolites and in T modesta cultures supplemented with 200 VM TNT demonstrated that the TNT biodegradation process lead to less toxic metabolites. Toxicity decreased in the order TNT > 4-HADNT (4-hydroxylaminodinitrotoluene) > 2-HADNT > 2,6-DNT (2,6-dinitrotoluene) > 2xxx,2xxx,6,6-azoxytetranitrotoluene > 4-AMDNT > 2-AMDNT > 2,4-diamninonitrotoluene (2,4-DAMNT) while 2,4-DNT and 2,6-DAMNT were the least toxic. Ferulic acid is the best candidate for immobilization TNT biodegradation metabolites since it prevented the accumulation of AMDNTs in cultures during TNT biodegradation and its products were less toxic. All humic monomers were very effective in immobilizing 2-HADNT [100%], 4-HADNT [100%] and 2,2,6,6-azoxytetranitrotoluene [100%]. Two distinct laccase isoenzymes (LTM1 and LTM2) potentially involved in immobilization of TNT degradation products were purified to electrophoretic homogeneity. LTM1 and LTM2 have molecular weights of 77.6 and 52.5 kDa, are 18% and 24% glycosylated, have pI values of 3.6 and 4.2, respectively. Both enzymes oxidized all the typical laccase substrates tested. LTM1 showed highest kinetic constants (K-m = 0.03 mu M; K-cat = 8.84 x 10(7) s(-1)) with syringaldazine as substrate. (c) 2006 Elsevier Ltd. All rights reserved.
Autor*innen der BOKU Wien:
Gübitz Georg
Nyanhongo Gibson Stephen
Find related publications in this database (using NML MeSH Indexing)
Aliivibrio fischeri - drug effects
Basidiomycota - enzymology
Biodegradation, Environmental -
Electrophoresis, Polyacrylamide Gel -
Enzyme Stability -
Humic Substances -
Hydrogen-Ion Concentration -
Isoenzymes -
Kinetics -
Laccase - metabolism
Oxidation-Reduction -
Substrate Specificity -
Temperature -
Trinitrotoluene - analysis

Find related publications in this database (Keywords)
biotransformation
immobilization
toxicity
laccase
Trametes modesta


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