Billions of pounds of phenol are produced and used anually in the United States. The largest single use of phenol is in the production of plastics, but it is also used in the synthesis of caprolactam, a precursor for nylon 6 and other man-made fibers. Phenolic compounds are among the most prominent ground water contaminants.
Although it is synthesized industrially, phenol is also found naturally in animal wastes and other organic materials. It is often formed by the activity of microorganisms, which can chemically modify a variety of xenobiotic and naturally occurring phenolic compounds. The aerobic phenol degradation pathway is shown elsewhere.
Lack and Fuchs (1994) propose that, in the denitrifying Pseudomonas strain K 172, a phenol kinase transfers a phosphate group from an unknown donor to phenol, forming phenylphosphate which is then further metabolized. He and Wiegel (1995) show that 4-hydroxybenzoate decarboxylase catalyzes the conversion of phenol to 4-hydroxybenzoate via anaerobic carboxylation in a Clostridium species.
The following is a text-format anaerobic phenol degradation pathway map. Organisms which can initiate the pathway are given, but other organisms may also carry out later steps. Follow the links for more information on compounds or reactions. This map is also available in graphic (9k) format.
Phenol Phenol Pseudomonas sp. strain K172 Clostridium | hydroxybenzoicum JW/Z-1T phenylphosphate | | synthase | | | | Phenylphosphate | 4-hydroxybenzoate | | decarboxylase phenylphosphate | | carboxylase | | | | +--------------+--------------+ | v 4-Hydroxybenzoate | | | 4-hydroxybenzoate-CoA ligase | v 4-Hydroxybenzoyl-CoA | | | 4-hydroxybenzoyl-CoA reductase | v Benzoyl CoA | | | v to the Anaerobic Benzoate Pathway
Page Author(s): Jessica Bell, Eva Young, and Stephen Stephens
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