Nitroaromatic compounds are recognized as environmentally hazardous and widely used for the industrial production of dyes, pesticides, plasticizers, explosives and solvents. Both oxidative and reductive mechanisms for degradation of nitrophenol compounds have been reported. A Moraxella sp. utilizes 4-nitrophenol as a sole source of carbon and nitrogen via an initial monooxygenase-catalyzed elimination of nitrite (Spain, J.C.; Gibson, D.T., 1991. Pathway for degradation of p-nitrophenol in a Moraxella sp. Applied and Environmental Microbiology. 57: 812-819; S. Nishino, personal communication, 2003). Similar monooxygenase reactions in Arthrobacter sp. strain JS443 and Arthrobacter protophormiae RKJ100 remove nitrite from 4-nitrophenol or 4-nitrocatechol in preparation for ring cleavage (Jain et al., 1994; Chauhan et al., 2000). Pseudomonas putida B2 and Alcaligenes sp. NyZ215 also employ a monooxygenase for the removal of nitrite from 2-nitrophenol to produce the ring cleavage substrate, catechol (Zeyer et al., 1986 and Xiao et al., 2007).
Under aneraobic conditions, Ralstonia eutropha JMP 134 and Pseudomonas putida B2 initially reduce the nitro group of 3-nitrophenol to form the hydroxylamino derivative. A mutase reaction, similar to the acid-catalyzed Bamberger rearrangement, converts 3-hydroxyaminophenol to aminohydroquinone (Schenzle et al., 1999) or 4-aminocatechol (Zhao et al., 2000). Meulenberg et al. (1996) reported the formation of 1,2,4-benzenetriol, which is proposed to form via a monooxygenase-type oxidation and elimination of ammonia.
Resorcinol is used in the manufacture of adhesives and dyes and as an ingredient in pharmaceutical preparations for the topical treatment of skin conditions. Phenol 2-monooxygenase hydroxylates resorcinol by reducing flavin with molecular oxygen.
The following is a text-format 4-nitrophenol 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 format.
Graphical Map (15k) | Graphical Map (6k)
from the
Parathion and Nitrofen
+--------- Pathways --------------------------------> 4-Nitrophenol 3-Nitrophenol 2-Nitrophenol
| | Arthrobacter protophormiae Ralstonia eutropha JMP 134 Pseudomonas putida B2
| | RKJ100 Pseudomonas putida B2 Alcaligenes sp. NyZ215
| | Arthrobacter sp. JS443 | |
| v | | | 2-nitrophenol
from the | 4-Nitrophenol | 4-nitrophenol | 3-nitrophenol | 2-monooxygenase
Bisphenol A, | Moraxella sp. | 2-monooxygenase | nitroreductase |
Bisphenol F, | | | | |
4-Nonylphenol, | | 4-nitrophenol v v v
4-Hydroxy- | | 4-monooxygenase 4-Nitrocatechol 3-Hydroxylaminophenol Catechol
acetophenone, | | | | |
gamma-Lindane | | | 4-nitrocatechol +---------+---------+ |
and Vanillin | | 2-Hydroxy-1,4-benzoquinone <--------------+ 4-monooxygenase | | |
Pathways | | | | ^ | 3-hydroxyl- | 3-hydroxyl- v
| | | | 2-hydroxy-1,4- | | | aminophenol | aminophenol to the
| +------------>| | benzoquinone | | | mutase | mutase Nitrobenzene
| | | 2-reductase | | | | Pathway
| | | | | v v
| | | | | Aminohydroquinone 4-Aminocatechol
| | | hydroxy- | | | |
| v v benzoquinone | | | |
| +-------- p-Benzoquinone reductase | | 1,2,4- aminohydroquinone v v 4-aminocatechol
| | | | benzenetriol oxidase | | oxidase
| | p-benzoquinone | | dehydrogenase | |
| | reductase | | +---------+---------+
| | hydroquinone | | |
| v hydroxylase v | |
+---> Hydroquinone -----------------------------> 1,2,4-benzenetriol <---------------------------------+
C. parapsilosis CBS604 | ^
| | | phenol
| hydroquinone | | 2-mono-
| 1,2-dioxygenase | | oxygenase
| | |
V | Resorcinol
cis,cis-4-Hydroxymuconic |
semialdehyde |
| |
| 4-hydroxymuconic | 1,2,4-
| semialdehyde | benzenetriol
| dehydrogenase | dioxygenase
v |
Maleylacetate <-----------------------------------+
|
| maleylacetate
| reductase
|
v
3-Oxoadipate
|
| 3-oxoadipate
| CoA-transferase
|
v
3-Oxoadipyl-CoA <------ from the Cyclohexane Pathway
|
| acetyl-CoA
| C-acyltransferase
|
v
Acetyl-CoA + Succinyl-CoA
| |
| |
| |
v v
Intermediary Intermediary
Metabolism Metabolism
(KEGG) (KEGG)
Page Author(s): Hugh McTavish, Gunjan Pandey, Prasad Kotharu and Michael Turnbull
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