Biodegradation of the chlorophenoxy herbicide (R)-(+)-mecoprop by Alcaligenes denitrificans

Tett, V.A. and Willetts, A.J. and Lappin-Scott, H.M. (1997) Biodegradation of the chlorophenoxy herbicide (R)-(+)-mecoprop by Alcaligenes denitrificans. Biodegradation, 8 (1). pp. 43-52. ISSN 0923-9820. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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An Alcaligenes denitrificans strain capable of utilizing the herbicide (R)-(+)-2(2-methyl-4-chlorophenoxy)propionic acid (mecoprop) as a sole carbon source was isolated from soil and cultured in liquid medium. Crude cell extracts of the bacterium were utilized in spectrophotometric assays to elucidate a biochemical pathway for degradation of mecoprop. Results indicated a reaction sequence analogous to the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). GC-MS analysis provided direct evidence for the biotransformation of mecoprop to the transient metabolite 4-chloro-2-methylphenol (MCP). No NADPH-dependent activity was observed during this reaction. Pyruvate was verified as the second product derived from the aliphatic side chain of mecoprop. MCP was subsequently transformed to a substituted catechol by an NADPH-dependent monooxygenase. When grown on mecoprop, A. denitrificans was adapted to oxidize catechol and its 3- and 3-methylated derivatives indicating the broad substrate specificity of catechol dioxygenase. The microorganism was demonstrated to adopt the ortho mechanism of aromatic cleavage which resulted in the formation of 2-methyl-3-carboxymethylene but-2-en-4-olide, a reaction intermediate of the beta-ketoadipate pathway.

Item Type: Article
Uncontrolled keywords: Alcaligenes denitrificans; biodegradation; chloroaromatic; mecoprop (R)-(+)-2(2-methyl-4-chlorophenoxy)propio
Subjects: Q Science > QR Microbiology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: T.J. Sango
Date Deposited: 23 Sep 2009 12:13
Last Modified: 18 Jul 2014 10:05
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