Degradation of 4-fluorophenol by Arthrobacter sp. strain IF1.
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.
Ferreira
Maria Isabel M
MI
Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL-9747 AG, Groningen, The Netherlands.
Marchesi
Julian R
JR
Janssen
Dick B
DB
D001173:Arthrobacter / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D006873:Hydroquinones / Q000378:metabolism; D008969:Molecular Sequence Data; D010636:Phenols / Q000032:analysis / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D006873:Hydroquinones; D010636:Phenols; D012336:RNA, Ribosomal, 16S; C106880:4-fluorophenol; C031927:hydroquinone