Ethylbenzene is one of the most water soluble aromatic hydrocarbons. Under aerobic conditions ethylbenzene degradation involves oxygenase reactions. Anaerobic ethylbenzene mineralization under denitrifying conditions was demonstrated for pure bacterial cultures (Rabus and Widdel 1995 and Ball et al. 1996).
Anaerobic degradation of ethylbenzene is initiated by a dehydrogenation of ethylbenzene to 1-phenyl ethanol, and subsequent conversion to benzoate (or benzoyl-CoA). Benzoate (or benzoyl-CoA) is a central intermediate in anaerobic degradation of a variety of aromatic hydrocarbons. The tentative pathway for anaerobic ethylbenzene oxidation to benzoate was compiled from Ball et al. 1996. 1-Phenylethanol, acetophenone, benzoate, and acetate were identified as intermediates. Compounds in brackets were not identified yet but postulated based on other experiments. Reversibility of individual reactions involved has not been addressed. The source of metabolic energy for acetophenone carboxylation has not yet been identified. Activities of benzoyl acetate-CoA ligase and benzoyl acetyl-CoA thiolase were not demonstrated directly.
The following is a text-format ethylbenzene anaerobic degradation pathway map. An organism which can initiate the pathway is 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.
Ethylbenzene
Unclassified Proteobacteria
strain EB1
|
|
| ethylbenzene
| dehydrogenase
|
v
1-Phenylethanol
|
|
| 1-phenylethanol
| dehydrogenase
|
v
Acetophenone
|
|
| acetophenone
| carboxylase
|
v
[Benzoyl acetate]
|
|
| benzoyl acetate-CoA
| ligase
|
v
[Benzoyl acetyl-CoA]
|
|
| benzoyl acetyl-CoA
| thiolase
|
v
Benzoyl-CoA + Acetyl-CoA
| |
| |
| |
| |
| |
V V
to the Intermediary
Anaerobic Benzoate Metabolism (KEGG)
Pathway
Page Author(s): Alfred Spormann and Ryan McLeish
March 31, 2008 Contact Us
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