Archives of Microbiology

, Volume 152, Issue 6, pp 594–599

Anaerobic degradation of phenol via carboxylation to 4-hydroxybenzoate: in vitro study of isotope exchange between 14CO2 and 4-hydroxybenzoate

Authors

  • Andreas Tschech
    • Angewandte MikrobiologieUniversität Ulm
  • Georg Fuchs
    • Angewandte MikrobiologieUniversität Ulm
Original Papers

DOI: 10.1007/BF00425493

Cite this article as:
Tschech, A. & Fuchs, G. Arch. Microbiol. (1989) 152: 594. doi:10.1007/BF00425493

Abstract

Extracts of denitrifying bacteria grown anaerobically with phenol and nitrate catalyzed an isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate. This exchange reaction is ascribed to a novel enzyme, phenol carboxylase, initiating the anaerobic degradation of phenol by para-carboxylation to 4-hydroxybenzoate. Some properties of this enzyme were determined by studying the isotope exchange reaction. Phenol carboxylase was rapidly inactivated by oxygen; strictly anoxic conditions were essential for preserving enzyme activity. The exchange reaction specifically was catalyzed with 4-hydroxybenzoate but not with other aromatic acids. Only the carboxyl group was exchanged; [U-14C]phenol was not exchanged with the aromatic ring of 4-hydroxybenzoate. Exchange activity depended on Mn2+ and inorganic phosphate and was not inhibited by avidin. Ortho-phosphate could not be substituted by organic phosphates nor by inorganic anions; arsenate had no effect. The pH optimum was between pH 6.5–7.0. The specific activity was 100 nmol 14CO2 exchange · min-1 · mg-1 protein. Phenol grown cells contained 4-hydroxybenzoyl CoA synthetase activity (40 nmol · min-1 · mg-1 protein). The possible role of phenol carboxylase and 4-hydroxybenzoyl CoA synthetase in anaerobic phenol metabolism is discussed.

Key words

Anaerobic degradationAromatic compoundsPhenol4-HydroxybenzoateCarboxylationPseudomonas sp.
Download to read the full article text

Copyright information

© Springer-Verlag 1989