title: The quantity and quality of dissolved organic matter as supplementary carbon source impacts the pesticide-degrading activity of a triple-species bacterial biofilm.
abstract: Effects of environmental dissolved organic matter (eDOM) that consists of various low concentration carbonic compounds on pollutant biodegradation by bacteria are poorly understood, especially when it concerns synergistic xenobiotic-degrading consortia where degradation depends on interspecies metabolic interactions. This study examines the impact of the quality and quantity of eDOM, supplied as secondary C-source, on the structure, composition and pesticide-degrading activity of a triple-species bacterial consortium in which the members synergistically degrade the phenylurea herbicide linuron, when grown as biofilms. Biofilms developing on 10 mg L⁻¹ linuron showed a steady-state linuron degradation efficiency of approximately 85 %. The three bacterial strains co-localized in the biofilms indicating syntrophic interactions. Subsequent feeding with eDOM or citrate in addition to linuron resulted into changes in linuron-degrading activity. A decrease in linuron-degrading activity was especially recorded in case of co-feeding with citrate and eDOM of high quality and was always associated with accumulation of the primary metabolite 3,4-dichloroaniline. Improvement of linuron degradation was especially observed with more recalcitrant eDOM. Addition of eDOM/citrate formulations altered biofilm architecture and species composition but without loss of any of the strains and of co-localization. Compositional shifts correlated with linuron degradation efficiencies. When the feed was restored to only linuron, the linuron-degrading activity rapidly changed to the level before the mixed-substrate feed. Meanwhile only minor changes in biofilm composition and structure were recorded, indicating that observed eDOM/citrate effects had been primarily due to repression/stimulation of linuron catabolic activity rather than to biofilm characteristics.
authors: Division of Soil and Water Management, Department of Earth and Environmental Sciences, Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 20-bus 2459, B-3001, Heverlee, Belgium, benjamin.horemans@ees.kuleuven.be.
authors: Benjamin
authors: B
authors: Horemans
authors: Johanna
authors: J
authors: Vandermaesen
authors: Philip
authors: P
authors: Breugelmans
authors: Johan
authors: J
authors: Hofkens
authors: Erik
authors: E
authors: Smolders
authors: Dirk
authors: D
authors: Springael
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D018407:Bacterial Physiological Phenomena / Q000187:drug effects*; D018441:Biofilms / Q000254:growth & development*; D001711:Biotransformation; D002244:Carbon / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism*; D008044:Linuron / Q000378:metabolism; D059013:Microbial Consortia / Q000187:drug effects* / Q000502:physiology*; D009930:Organic Chemicals / Q000378:metabolism*; D010575:Pesticides / Q000378:metabolism*
chemical_list: D000814:Aniline Compounds; D004785:Environmental Pollutants; D009930:Organic Chemicals; D010575:Pesticides; D008044:Linuron; C014464:3,4-dichloroaniline; D002244:Carbon