Regulation of chloro- and methylphenol degradation in Comamonas testosteroni JH5

Hollender, Juliane; Dott, Wolfgang; Hopp, Johanna

doi:10.1128/aem.60.7.2330-2338.1994

Cited by 42 publications

(15 citation statements)

References 34 publications

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“…The ability to degrade mixtures of compounds is crucial because groundwater is often contaminated with multiple pollutants. The ability to degrade mixtures of chloro-and methylphenols has been reported (Hollander et al 1994) and the degradation of mixtures of compounds was reviewed by Arcangeli and Arvin (1995).…”

Section: Discussionmentioning

confidence: 99%

4-Chlorophenol degradation by a bacterial consortium: development of a granular activated carbon biofilm reactor

Caldeira¹,

Heald

Carvalho³

et al. 1999

Applied Microbiology and Biotechnology

108

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A bacterial consortium that can degrade chloro- and nitrophenols has been isolated from the rhizosphere of Phragmitis communis. Degradation of 4-chlorophenol (4-CP) by a consortium attached to granular activated carbon (GAC) in a biofilm reactor was evaluated during both open and closed modes of operation. During the operation of the biofilm reactor, 4-CP was not detected in the column effluent, being either adsorbed to the GAC or biodegraded by the consortium. When 4-CP at 100 mg l-1 was fed to the column in open mode operation (20 mg g-1 GAC total supply), up to 27% was immediately available for biodegradation, the rest being adsorbed to the GAC. Biodegradation continued after the system was returned to closed mode operation, indicating that GAC bound 4-CP became available to the consortium. Biofilm batch cultures supplied with 10-216 mg 4-CP g-1 GAC suggested that a residual fraction of GAC-bound 4-CP was biologically unavailable. The consortium was able to metabolise 4-CP after perturbations by the addition of chromium (Cr VI) at 1-5 mg l-1 and nitrate at concentrations up to 400 mg l-1. The development of the biofilm structure was analysed by scanning electron microscopy and confocal laser scanning microscopy (CLSM) techniques. CLSM revealed a heterogeneous structure with a network of channels throughout the biofilm, partially occupied by microbial exopolymer structures.

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Section: Discussionmentioning

confidence: 99%

4-Chlorophenol degradation by a bacterial consortium: development of a granular activated carbon biofilm reactor

Caldeira¹,

Heald

Carvalho³

et al. 1999

Applied Microbiology and Biotechnology

108

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“…The catechol 2,3-dioxygenases of the meta pathway are able to convert catechol, both isomeric methylcatechols, and 4-chlorocatechol at respectable rates (10,18,27,33,38,44,47,48). The further degradation of the ring cleavage product of 4-chlorocatechol seems to be a slow process, since all strains degrading a chloroaromatic compound via 4-chlorocatechol through the meta pathway grow slowly on these substrates (1,2,15,16,29).…”

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confidence: 99%

Degradation of Chloroaromatics: Purification and Characterization of a Novel Type of Chlorocatechol 2,3-Dioxygenase of Pseudomonas putida GJ31

Kaschabek

Kasberg

Müller³

et al. 1998

J Bacteriol

107

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A purification procedure for a new kind of extradiol dioxygenase, termed chlorocatechol 2,3-dioxygenase, that converts 3-chlorocatechol productively was developed. Structural and kinetic properties of the enzyme, which is part of the degradative pathway used for growth of Pseudomonas putida GJ31 with chlorobenzene, were investigated. The enzyme has a subunit molecular mass of 33.4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Estimation of the native M r value under nondenaturating conditions by gel filtration gave a molecular mass of 135 ؎ 10 kDa, indicating a homotetrameric enzyme structure (4 ؋ 33.4 kDa). The pI of the enzyme was estimated to be 7.1 ؎ 0.1. The N-terminal amino acid sequence (43 residues) of the enzyme was determined and exhibits 70 to 42% identity with other extradiol dioxygenases. Fe(II) seems to be a cofactor of the enzyme, as it is for other catechol 2,3-dioxygenases. In contrast to other extradiol dioxygenases, the enzyme exhibited great sensitivity to temperatures above 40°C. The reactivity of this enzyme toward various substituted catechols, especially 3-chlorocatechol, was different from that observed for other catechol 2,3-dioxygenases. Stoichiometric displacement of chloride occurred from 3-chlorocatechol, leading to the production of 2-hydroxymuconate.

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“…Bacterial strain and culture conditions. Enrichment, identification, and growth of C. testosteroni JH5 were described previously (16). Strain JH5 was routinely grown at 27°C in a minimal medium with 4-CP (1 mM) and 4-MP (1 mM) in order to maintain specific degradation ability.…”

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confidence: 99%

Degradation of 4-Chlorophenol via the meta Cleavage Pathway by Comamonas testosteroni JH5

Hollender¹,

Hopp²,

Dott³

1997

Appl Environ Microbiol

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Comamonas testosteroni JH5 used 4-chlorophenol (4-CP) as its sole source of energy and carbon up to a concentration of 1.8 mM, accompanied by the stoichiometric release of chloride. The degradation of 4-CP mixed with the isomeric 2-CP by resting cells led to the accumulation of 3-chlorocatechol (3-CC), which inactivated the catechol 2,3-dioxygenase. As a result, further 4-CP breakdown was inhibited and 4-CC accumulated as a metabolite. In the crude extract of 4-CP-grown cells, catechol 1,2-dioxygenase and muconate cycloisomerase activities were not detected, whereas the activities of catechol 2,3-dioxygenase, 2-hydroxymuconic semialdehyde dehydrogenase, 2-hydroxymuconic semialdehyde hydrolase, and 2-oxopent-4-enoate hydratase were detected. These enzymes of the meta cleavage pathway showed activity with 4-CC and with 5-chloro-2hydroxymuconic semialdehyde. The activities of the dioxygenase and semialdehyde dehydrogenase were constitutive. Two key metabolites of the meta cleavage pathway, the meta cleavage product (5-chloro-2-hydroxymuconic semialdehyde) and 5-chloro-2-hydroxymuconic acid, were detected. Thus, our previous postulation that C. testosteroni JH5 uses the meta cleavage pathway for the complete mineralization of 4-CP was confirmed. The aerobic microbial degradation of many aromatic compounds occurs via catechols as key metabolites. The breakdown of catechols proceeds via the central step of ortho or meta ring fission. In general, methyl-substituted aromatic compounds are degraded via the meta cleavage pathway, whereas xenobiotics like chloroaromatic compounds are mineralized via the ortho cleavage pathway (9, 21). The degradation of methyl-and chloroaromatic substrates in mixture is often incomplete, leading to the accumulation of dead-end metabolites like chlorocatechols, chlorinated hydroxymuconic semialdehydes, or 4-carboxymethyl-methylbut-2-en-1,4-olides (31, 33). As a possible metabolite of chloroaromatic breakdown, 3-chlorocatechol (3-CC) reversibly inhibits the meta-cleaving catechol 2,3-dioxygenase or totally blocks the meta cleavage pathway by the irreversible suicide inactivation of this dioxygenase (4, 16, 20). Recently, we described Comamonas testosteroni JH5, which completely mineralizes a mixture consisting of 4-chlorophenol (4-CP) and monomethylphenols (16). The degradation of 4methylphenol (4-MP) and 4-CP occurred successively. Mixtures consisting of 4-CP and 2-MP or 3-MP were mineralized simultaneously. Since a catechol 2,3-dioxygenase, but no orthocleaving enzyme, was detected in cells grown on 4-CP, the mineralization of 4-CP via meta ring fission was postulated (16). Furthermore, a Pseudomonas species is able to completely mineralize 5-chlorovanillate via meta cleavage (18). Kersten et al. (18) showed that the formed acylchloride undergoes cyclization, which leads to a spontaneous removal of the chloride substituent. This mechanism is restricted to orthosubstituted halogens and therefore would not work with 4-CP. Recently, the meta cleavage of 4-chlorobenzoate by Pseudomonas cepacia ...

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Regulation of chloro- and methylphenol degradation in Comamonas testosteroni JH5

Cited by 42 publications

References 34 publications

4-Chlorophenol degradation by a bacterial consortium: development of a granular activated carbon biofilm reactor

4-Chlorophenol degradation by a bacterial consortium: development of a granular activated carbon biofilm reactor

Degradation of Chloroaromatics: Purification and Characterization of a Novel Type of Chlorocatechol 2,3-Dioxygenase of Pseudomonas putida GJ31

Degradation of 4-Chlorophenol via the meta Cleavage Pathway by Comamonas testosteroni JH5

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