Grantee Research Project Results
1998 Progress Report: Oxidative Coupling as a Cause of Substituent Release from Aromatic Pollutants
EPA Grant Number: R823847Title: Oxidative Coupling as a Cause of Substituent Release from Aromatic Pollutants
Investigators: Bollag, Jean-Marc , Dec, Jerzy
Institution: Pennsylvania State University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1995 through October 1, 1998 (Extended to September 30, 1999)
Project Period Covered by this Report: September 1, 1997 through October 1, 1998
Project Amount: $425,000
RFA: Exploratory Research - Chemistry and Physics of Water (1995) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Safer Chemicals
Objective:
The objective of this project is to obtain an insight into both condensation and degradation processes that comprise the interaction of various humic substances within the natural product realm with anthropogenic pollutants. The experimental approach relies on elucidating the pattern and mechanisms of substituent releases that occur when coupling reactions take place between and among monomeric substrates and polymeric humic substances.Progress Summary:
In the previous project periods (Oct. 95 - Sept. 96 and Oct. 96 - Sept. 97), the investigation was aimed at the quantification of dehalogenation and decarboxylation reactions to determine the sites on substrate molecules which are directly involved in oligomerization of the substrates or their binding to organic matter. In this project period (Oct. 97 - Sept. 98), the research focused on the demethoxylation and demethylation reactions, effect of humic acid on substrate transformation, and transformation of dioxin-like compounds. The reaction pathways were elucidated by chromatographic techniques (TLC, GC, and HPLC) and spectrometric methods (MS, IR, NMR).Halogens and carboxyl groups are not the only substituents that can be released from phenolic compounds via oxidative coupling reactions. As shown in the present project period, oxidoreductive catalysts can demethoxylate products of lignin degradation, such as vanillic acid or p-methoxyphenol, but they do not cause demethylation (release of the methyl group or higher aliphatic moieties). In soil environments, the methoxy group released in the form of methanol may undergo mineralization, resulting in CO2 evolution which may be mistakenly attributed to soil respiration. Humic substances are believed to have an inhibitory effect on enzymes involved in oxidative coupling. This project provided data showing that in many cases humic acid either enhanced or did not change the transformation of chlorinated phenols and anilines as compared with the transformation in the absence of humic acid. Since no data are available whether oxidoreductases may transform highly toxic dioxin-like xenobiotics, such as dibenzofurans and diphenylethers, to non-toxic oligomers, one of such compounds (2-hydroxydibenzofuran) was incubated in this project with laccases from white rot fungi to determine the transformation kinetics and the nature and fate of the reaction products.
Future Activities:
The project will continue to focus on the evaluation of oxidative coupling reactions. To better approximate field conditions, both humus constituents and xenobiotic compounds will be incubated with natural humic acid and soil. Emphasis will be put on the identification of the reaction products. Selected substrates will be labeled with 13C, 15N and 14C to facilitate the isolation of the resultant chemicals and their analysis by 13C and 15N NMR spectroscopy. The resolution of the spectra will be improved through derivatization of the formed complexes by silylation using trimethylchlorosilane, and through the application of 13C- and 15N- humic materials to eliminate background signals resulting from the natural abundance of these isotopes in soil. It is expected that the interactions determined in model experiments can be extrapolated to processes in soil environments.Journal Articles on this Report : 11 Displayed | Download in RIS Format
| Other project views: | All 20 publications | 19 publications in selected types | All 15 journal articles |
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Bollag JM, Dec J, Huang PM. Formation mechanisms of complex organic structures in soil habitats. Advances in Agronomy 1998;63:237-266. |
R823847 (1998) R823847 (Final) |
not available |
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Dec J, Bollag JM. Effect of various factors on dehalogenation of chlorinated phenols and anilines during oxidative coupling. Environmental Science & Technology 1995;29(3):657-663. |
R823847 (1998) R823847 (Final) |
not available |
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Dec J, Bollag JM. Determination of covalent and noncovalent binding interactions between xenobiotic chemicals and soil. Soil Science 1997;162(12):858-874. |
R823847 (1998) R823847 (Final) |
not available |
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Jonas U, Hammer E, Schauer F, Bollag JM. Transformation of 2-hydroxydibenzofuran by laccases of the white rot fungi Trametes versicolor and Pycnoporus cinnabarinus and characterization of oligomerization products. Biodegradation 1997;8(5):321-328. |
R823847 (1998) R823847 (Final) |
not available |
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Kim JE, Fernandes E, Bollag JM. Enzymatic coupling of the herbicide bentazon with humus monomers and characterization of reaction products. Environmental Science & Technology 1997;31(8):2392-2398. |
R823847 (1998) R823847 (Final) |
not available |
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Kim JE, Wang CJ, Bollag JM. Interaction of reactive and inert chemicals in the presence of oxidoreductases: reaction of the herbicide bentazon and its metabolites with humic monomers. Biodegradation 1997;8(6):387-392. |
R823847 (1998) R823847 (Final) |
not available |
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Naidja A, Huang PM, Bollag JM. Activity of tyrosinase immobilized on hydroxyaluminum-montmorillonite complexes. Journal of Molecular Catalysis A-Chemical 1997;115(2):305-316. |
R823847 (1998) R823847 (Final) |
not available |
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Naidja A, Huang PM, Bollag JM. Comparison of reaction products from the transformation of catechol catalyzed by birnessite or tyrosinase. Soil Science Society of America Journal 1998;62(1):188-195. |
R823847 (1998) R823847 (Final) |
not available |
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Park JW, Dec J, Kime JE, Bollag JM. Effect of humic constituents on the transformation of chlorinated phenols and anilines in the presence of oxidoreductive enzymes or birnessite. Environmental Science & Technology 1999;33(12):2028-2034. |
R823847 (1998) R823847 (Final) |
not available |
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Ricotta A, Unz RF, Bollag JM. Role of laccase in the degradation of pentachlorophenol. Bulletin of Environmental Contamination and Toxicology 1996;57(4):560-567. |
R823847 (1998) R823847 (Final) |
not available |
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Roper JC, Sarkar JM, Dec J, Bollag JM. Enhanced enzymatic removal of chlorophenols in the presence of co-substrates. Water Research, December 1995;29(12):2720-2724. |
R823847 (1998) R823847 (Final) |
not available |
Supplemental Keywords:
Humification; Phenoloxidases; Laccase; Enzymatic treatment; Clay minerals; Detoxification; Biodegradation; Pesticides; Wastewater., Scientific Discipline, Water, Physics, Environmental Chemistry, Chemistry, Engineering, Chemistry, & Physics, immunoassay, aromatic pollutants, oxidative coupling, anilinic compounds, dehalogenation, stochiometry, humification, phenolic compoundsRelevant Websites:
http://www.cos.com
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.