Degradation of fluorobenzene and its central metabolites 3-fluorocatechol and 2-fluoromuconate by Burkholderia fungorum FLU100

• Published in: Applied microbiology and biotechnology Vol. 97; no. 12; pp. 5605 - 5614
• Main Authors: Strunk, Niko, Engesser, Karl-Heinrich
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2013; Springer; Springer Nature B.V
• Subjects: acids; Analysis; attitudes and opinions; Bacteria; Benzene; Biodegradation; Biomedical and Life Sciences; Biotechnology; Biotransformation; Bromobenzene; Burkholderia; Burkholderia - classification; Burkholderia - genetics; Burkholderia - isolation & purification; Burkholderia - metabolism; Burkholderia fungorum; carbon; Carbon sources; Catechin; Catechol; chemistry; Chlorobenzene; Chlorophenol; Chromatography; classification; Cleavage; Degradation; DNA Transposable Elements; DNA, Bacterial; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Ribosomal; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; energy; Environmental Biotechnology; Enzymes; Experiments; Fluorobenzenes; Fluorobenzenes - metabolism; genetics; halides; Halobenzenes; Hydrocarbons; isolation & purification; Life Sciences; Metabolic Networks and Pathways; Metabolic Networks and Pathways - genetics; Metabolism; Metabolites; Microbial Genetics and Genomics; Microbiology; mineralization; Molecular Sequence Data; Muconic acid; Mutagenesis, Insertional; RNA, Ribosomal, 16S; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; Studies; Toluene; Transposon Tn5; Biodegradation; Fluorocatechol; Cleavage; Fluorobenzene; 2-Fluoromuconate; Fluoroaromatics
• ISSN: 0175-7598; 1432-0614; 1432-0614
• DOI: 10.1007/s00253-012-4388-2

A halobenzene-degrading bacterium, Burkholderia fungorum FLU100 (DSM 23736), was isolated due to its outstanding trait to degrade fluorobenzene. Besides fluorobenzene, it utilizes, even in random mixtures, chlorobenzene, bromobenzene, iodobenzene, benzene, and toluene as sole sources of carbon and energy. FLU100 mineralizes mono-halogenated benzenes almost stoichiometrically (according to halide balance); after a lag phase, it also degrades 3-fluorophenol and 3-chlorophenol completely. The FLU100-derived transposon Tn5-mutant FLU100-P14R22 revealed 3-halocatechol to be a central metabolite of this new halobenzene degradation pathway. In FLU100, halocatechols are—as expected—strictly subject to ortho -cleavage of the catechol ring, with meta -cleavage never been observed. The strain is able to completely mineralize 3-fluorocatechol, the principal catecholic metabolite being nearly exclusively formed from fluorobenzene. The temporarily excreted 2-fluoromuconate formed thereof in turn is subsequently metabolized completely. This important finding falsifies the customary opinion of the persistence of 2-fluoromuconate valid up to now. The degradation of 4-fluorocatechol, however, being a very minor intermediate in FLU100, is substantially slower and incomplete and leads to the accumulation of uncharacterized derivatives of muconic acid and muconolactone in the medium. This branch therefore does not seem to be productive. To our knowledge, this represents the first example of the complete metabolism of 3-fluorocatechol via 2-fluoromuconate, a metabolite hitherto described as a dead-end metabolite in fluoroaromatic degradation.