Trichloroethylene Pathway Map

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This pathway was started by Mark Whittaker and David Monroe, and completed by Dong Jun Oh and Sean Anderson, University of Minnesota.

Trichloroethylene (TCE) is a good solvent and is used in manufacturing to clean grease from machinery. It is one of the most abundant environmental pollutants of groundwater in the United States. In some groundwater, TCE undergoes reductive dechlorination catalyzed by anaerobic bacteria that yields vinyl chloride, a potent human carcinogen. TCE removal by dumping or air stripping is now largely disallowed and this has focused efforts on biological methods of TCE remediation in soil and water.

The enzyme that starts one branch of this pathway, toluene 1,2-dioxygenase, has many other catalytic abilities, which are documented in a table of the Reactions of Toluene 1,2-Dioxygenase.

The spontaneous degradation of trichloroethylene epoxide can produce as many as four products: dichloroacetate, carbon monoxide, glyoxylate, and formate. The number, type, and proportion of products seen depends on the local environment.

The following is a text-format trichloroethylene 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 (16k) format.

 

TCE                 TCE             TCE                             TCE            TCE
Methylosinus   Methylosinus    Burkholderia                         Ps.            Ps.
trichosporium  trichosporium    cepacia G4                       putida F1      putida F1
OB3b                OB3b             |                               |              | 
 |                   |               |      	                     |              |
 | soluble	     | sMMO          | toluene               toluene |      toluene |
 | methane	     |               | 2-monooxygenase   dioxygenase |  dioxygenase |
 | monooxygenase     |               |                               |              |
 | (sMMO)            |               |                               |              |
 |                   |               |                               v              v 
 |                   |               |                           Glyoxylate      Formate 
 |                   |               |                               |              |
 |                   |               |                               |              |
 v                   v               v                               v              v
Chloral              Trichloroethylene epoxide                  Intermediary      to the       
hydrate                   (TCE epoxide)                          Metabolism    C1 Metabolic 
 |                                   |                             (KEGG)         Cycle 
 |                                   |                                            
 |                  From the         |                                
 +---------------+  Trichloroethane  | spontaneous                          
 |               |  Pathway    |     |                            
 |               |             |     |                                                                     
 | dehydro-      | dehydro-    |     +----------------+--------------+--------------+
 | genase        | genase      |     |                |              |              |
 |               |             |     | B              | C            | D            | E
 v               v             |     |                |              |              |
Trichloro-  A    Trichloro- <--+     |                v              |              |
acetate   <--->  ethanol             |                |              |              |
Pseudomonas                          v                v              v              v
sp.                            Dichloroacetate       CO          Glyoxylate      Formate
 |                             Pseudomonas sp.        |              |              |
 |                                   |                |              |              | 
 +------------+                      |                v              v              v
 |            |                      |              to the      Intermediary      to the 
 | strain     | strain               |           Thiocyanate     Metabolism    C1 Metabolic 
 v PP3,       | 113                  |             Pathway         (KEGG)         Cycle
 | K5/5       | haloacid             | dichloro-                                  
 | E2         | dehalogenase         | acetate
 |            |                      | halidohyrolase
 v            v                      v
CO2        Oxalate               Glyoxylate
              |                      |
              |                      |
              |                      |
              v                      v
         Intermediary           Intermediary
          Metabolism             Metabolism 
            (KEGG)                 (KEGG)




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Page Author(s): Mark Whittaker, David Monroe, Dong Jun Oh and Sean Anderson

April 17, 2013 Contact Us

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