Unbound MEDLINE

Epoxy Coenzyme A Thioester pathways for degradation of aromatic compounds.

Abstract

Aromatic compounds (biogenic and anthropogenic) are abundant in the biosphere. Some of them are well-known environmental pollutants. Although the aromatic nucleus is relatively recalcitrant, microorganisms have developed various catabolic routes that enable complete biodegradation of aromatic compounds. The adopted degradation pathways depend on the availability of oxygen. Under oxic conditions, microorganisms utilize oxygen as a cosubstrate to activate and cleave the aromatic ring. In contrast, under anoxic conditions, the aromatic compounds are transformed to coenzyme A (CoA) thioesters followed by energy-consuming reduction of the ring. Eventually, the dearomatized ring is opened via a hydrolytic mechanism. Recently, novel catabolic pathways for the aerobic degradation of aromatic compounds were elucidated that differ significantly from the established catabolic routes. The new pathways were investigated in detail for the aerobic bacterial degradation of benzoate and phenylacetate. In both cases, the pathway is initiated by transforming the substrate to a CoA thioester and all the intermediates are bound by CoA. The subsequent reactions involve epoxidation of the aromatic ring followed by hydrolytic ring cleavage. Here we discuss the novel pathways, with a particular focus on their unique features and occurrence as well as ecological significance.

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  • Authors

    Ismail W, Gescher J

    Institution

    Biotechnology Program, College of Graduate Studies, Arabian Gulf University, Manama, Kingdom of Bahrain. waelame@agu.edu.bh

    Source

    Applied and environmental microbiology 78:15 2012 Aug pg 5043-51

    MeSH

    Biodegradation, Environmental
    Coenzyme A
    Epoxy Compounds
    Esters
    Hydrocarbons, Aromatic
    Hydrolysis
    Metabolic Networks and Pathways
    Molecular Structure
    Oxygen

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't
    Review

    Language

    eng

    PubMed ID

    22582071