Cresol is a mixture of o-, p-, and m-cresol, and is obtained from coal tar or petroleum. These isomers are used as a disinfectants, textile scouring agents, surfactants and as intermediates in the manufacture of salicylaldehyde, coumarin, and herbicides. Creosote is a less refined petrochemical mixture containing cresol. It is used as a fungicide and a wood preservative for railroad ties, telephone poles, and marine pilings. Despite their chemical similarity, cresol isomers are degraded by bacteria through different pathways.
One intermediate in this pathway, 3-hydroxybenzyl alcohol, is also an intermediate in the biosynthetic pathway of patulin (Grootwassink & Gaucher, 1980), a toxin and antiviral agent produced by some molds such as Penicillium patulinum.
When grown on m-cresol as a sole carbon source, P. putida 9869 metabolizes the compound via the meta pathway with 3-methylcatechol as an intermediate (Hopper et al., 1975). It has been shown that Pseudomonas picketti also degrade m-cresol via 3-methylcatechol, as presented in the Toluene Pathway (Shields et al., 1991).
Hopper and Taylor (1974) have also reported that P. putida 9869, when grown on 3,5-xylenol as a sole carbon source, metabolizes m-cresol via the gentisate pathway, as depicted in this text map. The genes coding for these enzymes are believed to be contained on a plasmid larger than the TOL plasmid which codes enzymes capable of degrading a many aromatic compounds (Hopper et al., 1980).
The following is a text-format m-cresol 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 (13k) format.
m-Cresol <---------> to and from the
(3-Hydroxytoluene) Toluene Pathway
Pseudomonas alcaligenes
NCIB 9867
Pseudomonas putida
NCIB 9869
|
| 3,5-xylenol
| methylhydroxylase
|
|
v
3-Hydroxybenzyl alcohol
|
| benzyl
| alcohol
| dehydrogenase
|
v
3-Hydroxybenzaldehyde
|
| benzaldehyde
| dehydrogenase
|
|
v
3-Hydroxybenzoate
|
|
|
+---------------------+
3-hydroxy- | | 3-hydroxy-
benzoate | | benzoate
6-hydroxylase | | 4-hydroxylase
| |
v v
2,5-Dihydroxy- 3,4-Dihydroxy-
benzoate benzoate
(Gentisate) (Protocatechuate)
| |
| |
| |
| |
v v
Intermediary to the
Metabolism 2,4-Dichlorobenzoate
(KEGG) Pathway
Page Author(s): Keiko Sakai and Stephen Stephens
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