title: Structural characterization of organic intermediates arising from xylenol degradation by laboratory-scale constructed wetlands.
abstract: A mixture of xylenols (2,6-, 3,4-, 3,5-) was subjected to laboratory-scale constructed wetland treatment using helophytes. Conversion efficiencies under aerobic conditions ranged from 89% to 94%; the corresponding numbers under anaerobic conditions were lower. The studies were focused on the identification of stable organic intermediates. Identification was performed by a combination of GC/MS analysis and pre-chromatographic derivatization of the lyophilizates. In addition to common intermediates including citraconate, succinate and dimethyl benzenediols, an array of α- and β-ketoadipic acid carboxylates could be identified. The ketoadipic acid carboxylates have not been known to be formed in bioremediation of phenols including xylenols so far. Mechanisms for the formation of ketoadipic acid carboxylates are proposed. Chemotaxonomic considerations using diagnostic fatty acids provided mounting evidence that organic matter originating from plants prevailed over bacterial organic matter. Biomarkers indicated a virtual absence of fungi and algae.
authors.affiliation: UFZ - Helmholtz Center for Environmental Research, Department of Environmental Engineering, Permoserstr. 15, D-04318 Leipzig, Germany. Electronic address: juergen.poerschmann@ufz.de.
authors.forename: J
authors.initials: J
authors.lastname: Poerschmann
authors.affiliation: UFZ - Helmholtz Center for Environmental Research, Department of Environmental Biotechnology, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Schultze-Nobre
mesh_terms: D001673:Biodegradation, Environmental; D002264:Carboxylic Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D007536:Isomerism; D007753:Laboratories; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis; D010944:Plants / Q000378:metabolism; D053833:Wetlands; D014992:Xylenes / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D010636:Phenols; D014992:Xylenes; C016834:3,5-xylenol
keywords: Constructed wetlands; Organic intermediates; Xylenols; β-Ketoadipate pathway