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Unspecific degradation of halogenated phenols by the soil fungus Penicillium frequentans Bi 7/2
Author(s) -
Hofrichter Martin,
Bublitz Friedemann,
Fritsche Wolfgang
Publication year - 1994
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620340306
Subject(s) - catechol , phenol , phenols , halogenation , 2,4 dichlorophenol , chemistry , catabolism , organic chemistry , fungus , stereochemistry , medicinal chemistry , enzyme , biology , bacteria , genetics , botany
Resting phenol‐grown mycelia of the fungus Penicillium frequentans strain Bi 7/2 were shown to be capable of metabolizing various monohalogenated phenols as well as 3,4‐dichlorophenol. 2,4.dichlorophenol could be metabolized in the presence of phenol as cosubstrate. In the first degradation step the halogenated phenols were oxidized to the corresponding halocatechols. Halocatechols substituted in para ‐position (4‐halocatechols) were further degraded under formation of 4‐carboxymethylenbut‐2‐en‐4‐olide. A partial dehalogenation took place splitting the ring system. 3‐Halocatechols were cleaved to 2‐halomuconic acids as dead end metabolites without a dehalogenation step. Dichlorophenols were only transformed to the corresponding catechols. In addition 3,5‐dichlorocatechol was O‐methylated to give two isomers of dichloroguaiacol. The halogenated catechols with the exception of 4‐fluorocatechol partly polymerized oxidatively in the culture fluid to form insoluble dark‐brown products. The degradation of halophenols are due to the action of unspecific intracellular enzymes responsible for phenol catabolism (phenol hydroxylase. catechol‐1,2‐dioxygenase, muconate cycloisomerase I).