Dechlorination of 1,2,3- and 1,2,4-trichlorobenzene by the white-rot fungus Trametes versicolor.
The degradation of 1,2,3-, 1,3,5- and 1,2,4-trichlorobenzene (TCB) by the white-rot fungus Trametes versicolor was studied. Time course experiments showed a degradation rate of 2.27 and 2.49 nmol d(-1)mg(-1) dry weight of biomass during the first 4d of incubation in cultures spiked with 6 mg L(-1) of 1,2,3- and 1,2,4-TCB, respectively. A high percent of degradation of 91.1% (1,2,3-TCB) and 79.6 (1,2,4-TCB) was obtained after 7d. However, T. versicolor was not able to degrade 1,3,5-TCB under the conditions tested. For a range of concentrations of 1,2,4-TCB between 6.5 and 23 mg L(-1), a complete dechlorination of the molecule was observed. Cytochrome P450 monooxygenase appears to be involve in the first step of 1,2,4-TCB degradation, as evidenced by marked inhibition of both dechlorination and degradation of 1,2,4-TCB in the presence of the known cyt P450 inhibitors 1-aminobenzotriazole and piperonyl butoxide. Four intermediates formed from 1,2,4-TCB degradation were detected the second day of incubation, which did not appear the seventh day: 2,3,5-trichloromuconate, its corresponding carboxymethylenebutenolide, 2- or 5-chloro-4-oxo-2-hexendioic acid and 2- or 5-chloro-5-hydroxy-4-oxo-2-pentenoic acid. Based on these results, a degradation pathway of 1,2,4-TCB through cyt P450 monooxygenase and epoxide hydrolase was proposed.
Marco-Urrea
Ernest
E
Departament d'Enginyeria Química and Institut de Ciència i Tecnologia Ambiental, Escola Tècnica Superior d'Enginyeria (ETSE), Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Spain.
Pérez-Trujillo
Miriam
M
Caminal
Gloria
G
Vicent
Teresa
T
D001673:Biodegradation, Environmental; D018533:Biomass; D001711:Biotransformation; D002722:Chlorobenzenes / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D054879:Halogenation; D007700:Kinetics; D053858:Metabolic Networks and Pathways; D055454:Trametes / Q000378:metabolism*
D002722:Chlorobenzenes; D005656:Fungal Proteins; C009947:1,2,4-trichlorobenzene; C036720:trichlorobenzene; D003577:Cytochrome P-450 Enzyme System