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Degradation of 4-fluorophenol by Arthrobacter sp. strain IF1.

Ferreira MI, Marchesi JR, Janssen DB - Appl. Microbiol. Biotechnol. (2008)

Bottom Line: Cell-free extracts of 4-FP-grown cells contained no activity for catechol 1,2-dioxygenase or catechol 2,3-dioxygenase, which indicates that the pathway does not proceed through a catechol intermediate.During 4-FP metabolism, hydroquinone accumulated as a product.These results indicate that the biodegradation of 4-FP starts with a 4-FP monooxygenase reaction that yields benzoquinone, which is reduced to hydroquinone and further metabolized via the beta-ketoadipic acid pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL-9747 AG, Groningen, The Netherlands.

ABSTRACT
A Gram-positive bacterial strain capable of aerobic biodegradation of 4-fluorophenol (4-FP) as the sole source of carbon and energy was isolated by selective enrichment from soil samples collected near an industrial site. The organism, designated strain IF1, was identified as a member of the genus Arthrobacter on the basis of 16S ribosomal RNA gene sequence analysis. Arthrobacter strain IF1 was able to mineralize 4-FP up to concentrations of 5 mM in batch culture. Stoichiometric release of fluoride ions was observed, suggesting that there is no formation of halogenated dead-end products during 4-FP metabolism. The degradative pathway of 4-FP was investigated using enzyme assays and identification of intermediates by gas chromatography (GC), GC-mass spectrometry (MS), high-performance liquid chromatography, and liquid chromatography-MS. Cell-free extracts of 4-FP-grown cells contained no activity for catechol 1,2-dioxygenase or catechol 2,3-dioxygenase, which indicates that the pathway does not proceed through a catechol intermediate. Cells grown on 4-FP oxidized 4-FP, hydroquinone, and hydroxyquinol but not 4-fluorocatechol. During 4-FP metabolism, hydroquinone accumulated as a product. Hydroquinone could be converted to hydroxyquinol, which was further transformed into maleylacetic acid and beta-ketoadipic acid. These results indicate that the biodegradation of 4-FP starts with a 4-FP monooxygenase reaction that yields benzoquinone, which is reduced to hydroquinone and further metabolized via the beta-ketoadipic acid pathway.

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Biodegradation of 4-FP and fluoride liberation in a batch culture of strain IF1. The carbon source used is 1 mM 4-FP. Symbols: triangles, 4-FP concentration; diamonds, optical density; squares, fluoride concentration
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Fig3: Biodegradation of 4-FP and fluoride liberation in a batch culture of strain IF1. The carbon source used is 1 mM 4-FP. Symbols: triangles, 4-FP concentration; diamonds, optical density; squares, fluoride concentration

Mentions: Growth on 4-FP and formation of metabolites A batch culture of strain IF1 supplied with 1 mM 4-FP as the only source of carbon and energy was monitored in time. Growth was accompanied by an increase in biomass, decrease in 4-FP, and formation of fluoride (Fig. 3). After 120 h, there was complete conversion of 1 mM 4-FP, and 1 mM fluoride was formed, indicating that there was no transient accumulation of fluorinated intermediates over the whole growth period. When cells grown on 4-FP were incubated in the presence of the iron chelator 2,2′-dipyridyl, no 4-FP degradation occurred, and no fluoride was released in the medium. This indicates that initial or further enzymes involved in 4-FP metabolism require ferrous ions for activity.Fig. 3


Degradation of 4-fluorophenol by Arthrobacter sp. strain IF1.

Ferreira MI, Marchesi JR, Janssen DB - Appl. Microbiol. Biotechnol. (2008)

Biodegradation of 4-FP and fluoride liberation in a batch culture of strain IF1. The carbon source used is 1 mM 4-FP. Symbols: triangles, 4-FP concentration; diamonds, optical density; squares, fluoride concentration
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2266783&req=5

Fig3: Biodegradation of 4-FP and fluoride liberation in a batch culture of strain IF1. The carbon source used is 1 mM 4-FP. Symbols: triangles, 4-FP concentration; diamonds, optical density; squares, fluoride concentration
Mentions: Growth on 4-FP and formation of metabolites A batch culture of strain IF1 supplied with 1 mM 4-FP as the only source of carbon and energy was monitored in time. Growth was accompanied by an increase in biomass, decrease in 4-FP, and formation of fluoride (Fig. 3). After 120 h, there was complete conversion of 1 mM 4-FP, and 1 mM fluoride was formed, indicating that there was no transient accumulation of fluorinated intermediates over the whole growth period. When cells grown on 4-FP were incubated in the presence of the iron chelator 2,2′-dipyridyl, no 4-FP degradation occurred, and no fluoride was released in the medium. This indicates that initial or further enzymes involved in 4-FP metabolism require ferrous ions for activity.Fig. 3

Bottom Line: Cell-free extracts of 4-FP-grown cells contained no activity for catechol 1,2-dioxygenase or catechol 2,3-dioxygenase, which indicates that the pathway does not proceed through a catechol intermediate.During 4-FP metabolism, hydroquinone accumulated as a product.These results indicate that the biodegradation of 4-FP starts with a 4-FP monooxygenase reaction that yields benzoquinone, which is reduced to hydroquinone and further metabolized via the beta-ketoadipic acid pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL-9747 AG, Groningen, The Netherlands.

ABSTRACT
A Gram-positive bacterial strain capable of aerobic biodegradation of 4-fluorophenol (4-FP) as the sole source of carbon and energy was isolated by selective enrichment from soil samples collected near an industrial site. The organism, designated strain IF1, was identified as a member of the genus Arthrobacter on the basis of 16S ribosomal RNA gene sequence analysis. Arthrobacter strain IF1 was able to mineralize 4-FP up to concentrations of 5 mM in batch culture. Stoichiometric release of fluoride ions was observed, suggesting that there is no formation of halogenated dead-end products during 4-FP metabolism. The degradative pathway of 4-FP was investigated using enzyme assays and identification of intermediates by gas chromatography (GC), GC-mass spectrometry (MS), high-performance liquid chromatography, and liquid chromatography-MS. Cell-free extracts of 4-FP-grown cells contained no activity for catechol 1,2-dioxygenase or catechol 2,3-dioxygenase, which indicates that the pathway does not proceed through a catechol intermediate. Cells grown on 4-FP oxidized 4-FP, hydroquinone, and hydroxyquinol but not 4-fluorocatechol. During 4-FP metabolism, hydroquinone accumulated as a product. Hydroquinone could be converted to hydroxyquinol, which was further transformed into maleylacetic acid and beta-ketoadipic acid. These results indicate that the biodegradation of 4-FP starts with a 4-FP monooxygenase reaction that yields benzoquinone, which is reduced to hydroquinone and further metabolized via the beta-ketoadipic acid pathway.

Show MeSH
Related in: MedlinePlus