Degradation of 2,4,6-trichlorophenol by Phanerochaete chrysosporium: involvement of reductive dechlorination

• Published in: Journal of Bacteriology 1998-10, Vol.180 (19), p.5159-5164
• Main Authors: Reddy, G.V.B. (Oregon Graduate Institute of Science and Technology, Portland, OR.), Sollewijn Gelpke, M.D, Gold, M.H
• Format: Article
• Language: English
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Bacteriology; Basidiomycota - metabolism; BIODEGRADACION; BIODEGRADATION; Biodegradation, Environmental; CHAMPIGNON; CHEMICAL REACTIONS; Chlorine; Chlorine - metabolism; Chlorophenols - metabolism; COMPOSE ORGANOCHLORE; COMPUESTO ORGANICO DEL CLORO; DEGRADACION; DEGRADATION; Environmental Pollutants - metabolism; ENZYMIC ACTIVITY; FUNGI; HONGOS; LIGNIN PEROXIDASE; MANGANESE PEROXIDASE; METABOLISM; METABOLISME; METABOLISMO; MICROBIAL DEGRADATION; MINERALISATION; MINERALIZACION; MINERALIZATION; Models, Chemical; ORGANOCHLORINE COMPOUNDS; OXIDACION; OXIDATION; Oxidation-Reduction; OXYDATION; PEROXIDASAS; PEROXIDASES; Peroxidases - metabolism; PEROXYDASE; PHANEROCHAETE CHRYSOSPORIUM; Physiology and Metabolism; Pollutants; REACCIONES QUIMICAS; REACTION CHIMIQUE; REDUCCION; REDUCTION
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/JB.180.19.5159-5164.1998

Under secondary metabolic conditions, the lignin-degrading basidiomycete Phanerochaete chrysosporium mineralizes 2,4,6-trichlorophenol. The pathway for the degradation of 2,4,6-trichlorophenol has been elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway is initiated by a LiP- or MnP-catalyzed oxidative dechlorination reaction to produce 2,6-dichloro-1,4-benzoquinone. The quinone is reduced to 2,6-dichloro-1,4-dihydroxybenzene, which is reductively dechlorinated to yield 2-chloro-1,4-dihydroxybenzene. The latter is degraded further by one of two parallel pathways: it either undergoes further reductive dechlorination to yield 1,4-hydroquinone, which is ortho-hydroxylated to produce 1,2,4-trihydroxybenzene, or is hydroxylated to yield 5-chloro-1,2,4-trihydroxybenzene, which is reductively dechlorinated to produce the common key metabolite 1,2,4-trihydroxybenzene. Presumably, the latter is ring cleaved with subsequent degradation to CO2. In this pathway, the chlorine at C-4 is oxidatively dechlorinated, whereas the other chlorines are removed by a reductive process in which chlorine is replaced by hydrogen. Apparently, all three chlorine atoms are removed prior to ring cleavage. To our knowledge, this is the first reported example of aromatic reductive dechlorination by a eukaryote