Styrene Degradation Pathway

Styrene Pathway Map

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This pathway was started by Dean Kraus, University of Minnesota, Kenneth E. Lind, University of Minnesota, and Andrea Marconi, Universita di Roma Tre and completed by Ryan McLeish, University of Minnesota.

When styrene is heated, exposed to light, or in the presence of a peroxide catalyst, it undergoes polymerization to form polystyrene, a versatile material used in the manufacture of plastics, synthetic rubber, thermal insulation, and packaging. Although polystyrene has many beneficial commercial applications, the styrene monomer is a classified mutagen and a suspected carcinogen. It is highly toxic to aquatic life, although its half-life is less than two days in water. There are several microorganisms that are capable of initiating styrene biodegradation, and metabolism proceeds via one of two known pathways; the principal reaction may either be an ethylene side-chain monooxygenation (Cox et al., 1996) or a 2,3-dioxygenation (Warhurst et al., 1994).

The following is a text-format styrene 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.

    Graphical Map (17k)                Graphical Map (13k)

          Styrene                            Styrene
     Exophiala jeanselmei         Rhodococcus rhodochrous NCIMB 13259
   Pseudomonas putida CA-3                      |
             |                                  |
             |                                  |
             | styrene                          | styrene
             | monooxygenase                    | dioxygenase
             |                                  |
             v                                  v
       Styrene oxide                    Styrene cis-glycol
             |                                  |
             |                                  |
             | styrene oxide                    | cis-glycol
             | isomerase                        | dehydrogenase
             |                                  |
             v                                  v
     Phenylacetaldehyde                  3-Vinylcatechol
             |                                  |
             |                                  |
             | phenylacetaldehyde               | catechol
             | dehydrogenase                    | 2,3-dioxygenase
             |                                  |
             v                                  v
       Phenylacetate                    2-Hydroxy-6-oxo-octa-
	     |                                 trienoate
	     |                                 /\
             v                                /  \
           to the                            /    \ 2-hydroxymuconate
       Phenylacetate                        /      \ semialdehyde hydrolase
          Pathway                          /        \
                                          v          v
                                    Acrylate  +   2-Hydroxypenta-
                                       |           2,4-dienoate
                                       |              |
                                       v              |
                                    to the            | 2-hydroxypenta-2,4-dienoate
                                    Acrylonitrile     | hydratase
                                    Pathway           |
                                                      v
                                           4-Hydroxy-2-oxovalerate
                                                     /\
                                                    /  \
                                                   /    \ 4-hydroxy-2-oxovalerate
                                                  /      \ aldolase
                                                 /        \
                                                v          v
                                         Acetaldehyde + Pyruvate |            | |            | |            | |            | v            v
                                         Intermediary  Intermediary
                                          Metabolism    Metabolism
                                            (KEGG)        (KEGG)

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Page Author(s): Dean Kraus, Andrea Marconi, Kenneth E. Lind and Ryan McLeish

October 11, 2013 Contact Us

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