Bacterial O-Methylation of Chloroguaiacols: Effect of Substrate Concentration, Cell Density, and Growth Conditions

Allard, Ann‐Sofie; Remberger, Mikael; Neilson, Alasdair H.

doi:10.1128/aem.49.2.279-288.1985

Cited by 52 publications

(27 citation statements)

References 44 publications

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“…The chloroanisoles produced by O-methylation are often less toxic to bacteria and fungi than the corresponding chlorophenols [43,113,[125][126][127], suggesting that O-methylation might function as a detoxification mechanism. However, the ability to O-methylate chlorophenols was found in strains enriched on chlorophenols and in strains that had no known previous exposure to a chlorophenol, indicating that the trait is not the results of adaptation to chlorophenols [108].…”

Section: Biotransformation Of Chlorinated Phenolic Compoundsmentioning

confidence: 99%

Microbial breakdown of halogenated aromatic pesticides and related compounds

Häggblom

1992

FEMS Microbiology Letters

363

132

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Considerable progress has been made in the last few years in understanding the mechanisms of microbial degradation of halogenated aromatic compounds. Much is already known about the degradation mechanisms under aerobic conditions, and metabolism under anaerobiosis has lately received increasing attention. The removal of the halogen substituent is a key step in degradation of halogenated aromatics. This may occur as an initial step via reductive, hydrolytic or oxygenolytic mechanisms, or after cleavage of the aromatic ring at a later stage of metabolism. In addition to degradation, several biotransformation reactions, such as methylation and polymerization, may take place and produce more toxic or recalcitrant metabolites. Studies with pure bacterial and fungal cultures have given detailed information on the biodegradation pathways of several halogenated aromatic compounds. Several of the key enzymes have been purified or studied in cell extracts, and there is an increasing understanding of the organization and regulation of the genes involved in haloaromatic degradation. This review will focus on the biodegradation and biotransformation pathways that have been established for halogenated phenols, phenoxyalkanoic acids, benzoic acids, benzenes, anilines and structurally related halogenated aromatic pesticides. There is a growing interest in developing microbiological methods for clean‐up of soil and water contaminated with halogenated aromatic compounds.

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Section: Biotransformation Of Chlorinated Phenolic Compoundsmentioning

confidence: 99%

Microbial breakdown of halogenated aromatic pesticides and related compounds

Häggblom

1992

FEMS Microbiology Letters

363

132

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“…Reference samples of the chloroguaiacols, chlorocatechols and chlorovanillins were synthesized in this laboratory [28,29]. Quantitative analysis of all of the chloro compounds was carried out using GC analysis of the 0-acetates, as described previously [30]. For identification, two additional derivatives were used, the 0-trimethylsilyl ether and the 0-ethyl ether.…”

Section: Procedures For Analysis a N D Identificationmentioning

confidence: 99%

Comparison of Procedures for Recovering Chloroguaiacols and Chlorocatechols From Contaminated Sediments

Remberger¹,

Hynning²,

Neilson³

1988

Environ Toxicol Chem

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Procedures for the extraction of chloroguaiacols and chlorocatechols from contaminated sediment samples were examined. Using one sample, a comparison was made of the following procedures: solvent extraction with water-miscible solvents, steam distillation, Soxhlet extraction with t-butyl methyl ether, and several more aggressive methods employing BF3/methanol, HBr/water and KOH/methanol. The recoveries of the chlorinated compounds were highly variable. Recovery of the chloroguaiacols by the nonaggressive procedures was generally low, but it was significantly greater using methanolic alkali. The efficacy of the latter procedure was confirmed by the data obtained with three other sediment samples. Qualitatively similar differences in recoverability were also observed when a high molecular weight alkali-stage chlorolignin was examined. Therefore it was not possible to determine whether the monomeric chlorinated compounds were bound to natural organic compounds in the sediment or to the chlorolignin, which is produced during the bleaching process. In an experiment using one sediment sample incubated under anaerobic conditions for nine months, no change occurred in the amount of extractable chloroguaiacols and there was an approximate 40% reduction in the corresponding chlorocatechols. It is therefore postulated that the binding mechanisms of the chloroguaiacols and chlorocatechols in the sediment phase are significantly different, and that an indeterminate fraction is not accessible to microbial transformation. There are, it is noted, inherent limitations to interpreting the results of experiments on binding and desorption in which xenobiotics are exposed to the sediment phase for only a short time.

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“…Analytical and identification procedures. Although analysis of substrates in the aqueous phase presented no problems and was carried out by methods used previously (1), it became clear early in this study that it is not possible to extract chloroguaiacols, chloroveratroles, or chlorocate-chols quantitatively from sediment samples by simple extractive procedures. The following precedures were designed to provide satisfactory extraction without destruction of the sensitive chlorocatechols and to remove organic sulfur compounds which seriously interfere with the gas chromatographic (GC) analysis.…”

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confidence: 97%

“…We have previously shown in laboratory experiments with pure cultures that a number of taxonomically different bacteria were able to bring about the 0-methylation of chlorinated guaiacols and phenols with the production of neutral veratroles and anisoles (17). In an attempt to obtain an environmental perspective on the possible significance of these observations, we examined the toxicity of these compounds and their metabolites to fish (18) and evaluated a number of factors which might influence 0-methylation under natural conditions-the effect of substrate concentrations, growth conditions, and cell density (1). A realistic assessment of the environmental significance of these observations requires, however, an analysis of the extent to which they occur in natural systems.…”

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Biotransformations of Chloroguaiacols, Chlorocatechols, and Chloroveratroles in Sediments

Remberger¹,

Allard²,

Neilson³

1986

Appl Environ Microbiol

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The occurrence of trichloro- and tetrachloroguaiacols, -catechols, and -veratroles and their transformation was studied in freshwater and brackish water sediments putatively exposed to bleachery discharge. The samples contained both chloroguaiacols and chlorocatechols, of which >90% could not be removed by simple extraction. The bound concentrations varied and ranged from 550 μg kg of organic C −1 for 3,4,5-trichloroguaiacol to 8,250 μg kg of organic C −1 for tetrachlorocatechol. Chlorinated substrates added to the aqueous phase were rapidly bound to the sediment with K p values between 1.3 and 2.8 ml kg of organic C −1 for the chloroguaiacols and chloroveratroles and 22 to 36 ml kg of organic C −1 for the chlorocatechols. Sediment samples incubated aerobically brought about O-methylation of 4,5,6-trichloroguaiacol to 3,4,5-trichloroveratrole in a yield of ca. 25%. Under anaerobic conditions, however, de-O-methylation of both the chloroguaiacols and chloroveratroles took place with synthesis of the corresponding chlorocatechols. In separate experiments, the chlorocatechols were not completely stable under anaerobic conditions, but their ultimate fate has not yet been resolved. Sediment which had been autoclaved twice at 121°C for 20 min was unable to bring about any of these transformations; we therefore conclude that they were mediated by biological processes. These results emphasize that, in determining the fate of chloroguaiacols and related compounds discharged into the aquatic environment, the cardinal roles of sorption to the sediment phase and of the oxygen tension must be taken into account. We propose a hypothetical guaiacol cycle to accommodate our observations.

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Bacterial O-Methylation of Chloroguaiacols: Effect of Substrate Concentration, Cell Density, and Growth Conditions

Cited by 52 publications

References 44 publications

Microbial breakdown of halogenated aromatic pesticides and related compounds

Microbial breakdown of halogenated aromatic pesticides and related compounds

Comparison of Procedures for Recovering Chloroguaiacols and Chlorocatechols From Contaminated Sediments

Biotransformations of Chloroguaiacols, Chlorocatechols, and Chloroveratroles in Sediments

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