Anaerobic O-demethylation of chlorinated guaiacols byAcetobacterium woodii andEubacterium limosum

Häggblom, Max M.; Berman, Mitchell H.; Frazer, Anne Cornish; Young, L. Y.

doi:10.1007/bf00702327

Cited by 11 publications

(4 citation statements)

References 27 publications

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“…In contrast, no adverse effects have been associated with the MeO-PBDEs as such, although methylation and demethylation of several anisoles and phenolic organic compounds via enzymatic reactions have been observed in, e.g., microorganisms Axelrod and Tomchick 1958;Häggblom et al 1993;Neilson et al 1987Neilson et al , 1988Valo and Salkinoja-Salonen 1986;Wan et al 2009). Consequently, perhaps, the OH-PBDEs and MeO-PBDEs should be considered together in evaluating exposure and potential toxic effects.…”

Section: Ecological Relevancementioning

confidence: 84%

Brominated phenols, anisoles, and dioxins present in blue mussels from the Swedish coastline

Löfstrand

Malmvärn

Haglund

et al. 2010

Environ Sci Pollut Res

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Section: Ecological Relevancementioning

confidence: 84%

Brominated phenols, anisoles, and dioxins present in blue mussels from the Swedish coastline

Löfstrand

Malmvärn

Haglund

et al. 2010

Environ Sci Pollut Res

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“…3A). Anaerobic O-demethylation of methoxylated aromatic compounds (2,6,8), including chlorinated aromatics (16), is well established, and the fungal CAM 3,5-dichloro-p-anisyl alcohol is demethylated in methanogenic sludge (46). Demethylation of methoxy groups is observed with homoacetogens that use the reaction for energy and a carbon source.…”

Section: Discussionmentioning

confidence: 99%

Microbial Anaerobic Demethylation and Dechlorination of Chlorinated Hydroquinone Metabolites Synthesized by Basidiomycete Fungi

Milliken¹,

Meier

Watts

et al. 2004

Appl Environ Microbiol

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The synthesis and degradation of anthropogenic and natural organohalides are the basis of a global halogen cycle. Chlorinated hydroquinone metabolites (CHMs) synthesized by basidiomycete fungi and present in wetland and forest soil are constituents of that cycle. Anaerobic dehalogenating bacteria coexist with basidiomycete fungi in soils and sediments, but little is known about the fate of these halogenated fungal compounds. In sediment microcosms, the CHMs 2,3,5,6-tetrachloro-1,4-dimethoxybenzene and 2,3,5,6-tetrachloro-4-methoxyphenol (TCMP) were anaerobically demethylated to tetrachlorohydroquinone (TCHQ). Subsequently, TCHQ was converted to trichlorohydroquinone and 2,5-dichlorohydroquinone (2,5-DCHQ) in freshwater and estuarine enrichment cultures. Screening of several dehalogenating bacteria revealed that Desulfitobacterium hafniense strains DCB2 and PCP1, Desulfitobacterium chlororespirans strain Co23, and Desulfitobacterium dehalogenans JW/DU1 sequentially dechlorinate TCMP to 2,3,5-trichloro-4-methoxyphenol and 3,5-dichloro-4-methoxyphenol (3,5-DCMP). After a lag, these strains demethylate 3,5-DCMP to 2,6-DCHQ, which is then completely dechlorinated to 1,4-dihydroquinone (HQ). 2,5-DCHQ accumulated as an intermediate during the dechlorination of TCHQ to HQ by the TCMP-degrading desulfitobacteria. HQ accumulation following TCMP or TCHQ dechlorination was transient and became undetectable after 14 days, which suggests mineralization of the fungal compounds. This is the first report on the anaerobic degradation of fungal CHMs, and it establishes a fundamental role for microbial reductive degradation of natural organochlorides in the global halogen cycle.

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“…Also, chlorinated methoxy aromatics can be demethylated by anaerobic bacteria. Häggblom et al (16) reported the anaerobic O demethylation of chlorinated guaiacols by the acetogenic bacteria Acetobacterium woodii and Eubacterium limosum. Anaerobic cell suspensions of both E. limosum and A. woodii were able to O demethylate di-, tri-, and tetrachloroguaiacols to the corresponding catechols, which accumulated and were not further metabolized.…”

Section: Discussionmentioning

confidence: 99%

Biotransformation of the Major Fungal Metabolite 3,5-Dichloro- p -Anisyl Alcohol under Anaerobic Conditions and Its Role in Formation of Bis(3,5-Dichloro-4-Hydroxyphenyl)methane

Verhagen¹,

Swarts²,

Wijnberg³

et al. 1998

Appl Environ Microbiol

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Higher fungi have a widespread capacity for biosynthesis of organohalogens. Commonly occurring chloroaromatic fungal metabolites can end up in anaerobic microniches at the boundary of fungal colonies and wetland soils. The aim of this study was to investigate the environmental fate of a major fungal metabolite, 3,5-dichloro-p-anisyl alcohol, under anaerobic conditions. This compound was incubated with methanogenic sludge to study its biotransformation reactions. Initially, 3,5-dichloro-p-anisyl alcohol was readily demethylated in stoichiometric quantities to 3,5-dichloro-4-hydroxybenzyl alcohol. The demethylated product was converted further via two routes: a biotic route leading to the formation of 3,5-dichloro-4-hydroxybenzoate and 2,6-dichlorophenol, as well as an abiotic route leading to the formation of bis(3,5-dichloro-4-hydroxyphenyl)methane. In the first route, the benzyl alcohol moiety on the aromatic ring was oxidized, giving 3,5-dichloro-4-hydroxybenzoate as a transient or accumulating product, depending on the type of methanogenic sludge used. In sludge previously adapted to low-molecular-weight lignin from straw, a part of the 3,5-dichloro-4-hydroxybenzoate was decarboxylated, yielding detectable levels of 2,6-dichlorophenol. In the second route, 3,5-dichloro-4-hydroxybenzyl alcohol dimerized, leading to the formation of a tetrachlorinated bisphenolic compound, which was identified as bis(3,5-dichloro-4-hydroxyphenyl)methane. Since formation of this dimer was also observed in incubations with autoclaved sludge spiked with 3,5-dichloro-4-hydroxybenzyl alcohol, it was concluded that its formation was due to an abiotic process. However, demethylation of the fungal metabolite by biological processes was a prerequisite for dimerization. The most probable reaction mechanism leading to the formation of the tetrachlorinated dimer in the absence of oxygen is presented, and the possible environmental implications of its natural occurrence are discussed.

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Anaerobic O-demethylation of chlorinated guaiacols byAcetobacterium woodii andEubacterium limosum

Cited by 11 publications

References 27 publications

Brominated phenols, anisoles, and dioxins present in blue mussels from the Swedish coastline

Brominated phenols, anisoles, and dioxins present in blue mussels from the Swedish coastline

Microbial Anaerobic Demethylation and Dechlorination of Chlorinated Hydroquinone Metabolites Synthesized by Basidiomycete Fungi

Biotransformation of the Major Fungal Metabolite 3,5-Dichloro- p -Anisyl Alcohol under Anaerobic Conditions and Its Role in Formation of Bis(3,5-Dichloro-4-Hydroxyphenyl)methane

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