Oxidative 4-dechlorination of polychlorinated phenols is catalyzed by extracellular fungal lignin peroxidases

Journal Article · Tue Aug 23 04:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00417a055· OSTI ID:6326308

Hammel, K E; Tardone, P J

The extracellular lignin peroxidases (ligninases) of Phanerochaete chrysosporium catalyzed H/sub 2/O/sub 2/-dependent spectral changes in several environmentally significant polychlorinated phenols: 2,4-dichloro-, 2,4,5-trichloro-, 2,4,6-trichloro-, and pentachlorophenol. Gas chromatography/mass spectrometry of reduced and acetylated reaction products showed that, in each case, lignin peroxidase catalyzed a 4-dechlorination of the starting phenol to yield a p-benzoquinone. The oxidation of 2,4-dichlorophenol also yielded a dechlorinated coupling dimer, tentatively identified as 2-chloro-6-(2,4-dichlorophenoxy)-p-benzoquinone. Experiments on the stoichiometry of 2,4,6-trichlorophenol oxidation showed that this substrate was quantitatively dechlorinated to give the quinone and inorganic chloride. H/sub 2//sup 18/O-labeling experiments on 2,4,6-trichlorophenol oxidation demonstrated that water was the source of the new 4-oxo substituent in 2,6-di-chloro-p-benzoquinone. The results indicate a mechanism whereby lignin peroxidase oxidizes a 4-chlorinated phenol to an electrophilic intermediate, perhaps the 4-chlorocyclohexadienone cation. Nucleophilic attack by water and elimination of HCl then ensue at the 4-position, which produces the quinone. Lignin peroxidases have previously been implicated in the degradation by Phanerochaete of several nonphenolic aromatic pollutants. It appears likely from their results that these peroxidases could also catalyze the initial dechlorination of certain polychlorinated phenols in vivo.

• Research Organization: State Univ. of New York, Syracuse (USA)
• OSTI ID: 6326308
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:17; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AROMATICS
BIOCHEMISTRY
CARBOHYDRATES
CHEMICAL REACTIONS
CHEMISTRY
CHLORINATED AROMATIC HYDROCARBONS
CHROMATOGRAPHY
DECHLORINATION
DEHALOGENATION
ENZYMES
EUMYCOTA
EVEN-EVEN NUCLEI
FUNGI
GAS CHROMATOGRAPHY
HALOGENATED AROMATIC HYDROCARBONS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INORGANIC ACIDS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIGNIN
MASS SPECTROSCOPY
NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDOREDUCTASES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PEROXIDASES
PHANEROCHAETE
PHENOLS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
WATER