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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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Fluoride release and biomass formation by strain IF1 with different concentrations of 4-FP. a Stoichiometric fluoride release. Symbols: squares, optical density at 600 nm; circles, fluoride concentration. b Growth in the presence of different levels of 4-FP. The initial concentrations used were: triangles, 1 mM 4-FP; circles, 4 mM 4-FP; diamonds, 5 mM 4-FP; squares, 7 mM 4-FP
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Fig2: Fluoride release and biomass formation by strain IF1 with different concentrations of 4-FP. a Stoichiometric fluoride release. Symbols: squares, optical density at 600 nm; circles, fluoride concentration. b Growth in the presence of different levels of 4-FP. The initial concentrations used were: triangles, 1 mM 4-FP; circles, 4 mM 4-FP; diamonds, 5 mM 4-FP; squares, 7 mM 4-FP

Mentions: To test the range of 4-FP concentrations tolerated by strain IF1, experiments were conducted in sealed flasks with 4-FP at concentrations of 1 to 7 mM as a sole carbon and energy source. Control assays without 4-FP showed no growth or release of fluoride, and sterile controls showed no abiotic loss of 4-FP. Between 1 and 4 mM 4-FP, the substrate was completely consumed, stoichiometric release of fluoride was observed, and biomass increased linearly with the amount of 4-FP added (Fig. 2a). This indicates that the degradation of 4-FP by strain IF1 does not give large amounts of fluorinated dead-end products. Concentrations of 4-FP above 4 mM caused a toxic effect on the growth of IF1 (Fig. 2b). The use of 5 mM 4-FP promoted growth, but a longer lag time was observed. At 7 mM 4-FP, no growth occurred even after 15 days of incubation.Fig. 2


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

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

Fluoride release and biomass formation by strain IF1 with different concentrations of 4-FP. a Stoichiometric fluoride release. Symbols: squares, optical density at 600 nm; circles, fluoride concentration. b Growth in the presence of different levels of 4-FP. The initial concentrations used were: triangles, 1 mM 4-FP; circles, 4 mM 4-FP; diamonds, 5 mM 4-FP; squares, 7 mM 4-FP
© Copyright Policy
Related In: Results  -  Collection

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

Fig2: Fluoride release and biomass formation by strain IF1 with different concentrations of 4-FP. a Stoichiometric fluoride release. Symbols: squares, optical density at 600 nm; circles, fluoride concentration. b Growth in the presence of different levels of 4-FP. The initial concentrations used were: triangles, 1 mM 4-FP; circles, 4 mM 4-FP; diamonds, 5 mM 4-FP; squares, 7 mM 4-FP
Mentions: To test the range of 4-FP concentrations tolerated by strain IF1, experiments were conducted in sealed flasks with 4-FP at concentrations of 1 to 7 mM as a sole carbon and energy source. Control assays without 4-FP showed no growth or release of fluoride, and sterile controls showed no abiotic loss of 4-FP. Between 1 and 4 mM 4-FP, the substrate was completely consumed, stoichiometric release of fluoride was observed, and biomass increased linearly with the amount of 4-FP added (Fig. 2a). This indicates that the degradation of 4-FP by strain IF1 does not give large amounts of fluorinated dead-end products. Concentrations of 4-FP above 4 mM caused a toxic effect on the growth of IF1 (Fig. 2b). The use of 5 mM 4-FP promoted growth, but a longer lag time was observed. At 7 mM 4-FP, no growth occurred even after 15 days of incubation.Fig. 2

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