title: Response to mixed substrate feeds of the structure and activity of a linuron-degrading triple-species biofilm.
abstract: We sought to determine whether the pesticide-degrading performance of a multi-species bacterial biofilm is affected by co-occurrence of multiple nutrient sources. Thus, the 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea (linuron)-degrading activity of a triple-species linuron-degrading consortium, cultivated in continuous flow biofilm systems, was monitored when exposed to mixed substrate feeds which contained, in addition to linuron, readily assimilated carbon (i.e. citrate and trypticase soy broth) and/or nitrogen (i.e. ammonium) sources. The addition of alternative carbon sources at different concentrations resulted in diminished linuron degradation efficiency. In addition, the efficiency of removal of the linuron metabolite 3,4-dichloroaniline was affected. These effects might be attributed to catabolic repression of the linuron metabolic pathway in the presence of alternative carbon substrates. Moreover, each nutrient condition resulted in a particular biofilm composition and a particular spatial and structural organization, which might also be related to the performance of the biofilm community. Results show that the activity of pesticide-degrading biofilms strongly depends on prevailing nutrient conditions and that the ideal biofilm configuration and activity, as observed under selective conditions, does not exist in real-life environmental conditions where mixtures of substrates are often present.
authors.affiliation: Division of Soil and Water Management, Catholic University of Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
authors.forename: Philip
authors.initials: P
authors.lastname: Breugelmans
authors.forename: Benjamin
authors.initials: B
authors.lastname: Horemans
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
authors.forename: Dirk
authors.initials: D
authors.lastname: Springael
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D001673:Biodegradation, Environmental; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism; D042621:Comamonadaceae / Q000378:metabolism*; D020604:Comamonas testosteroni / Q000378:metabolism; D003470:Culture Media; D017753:Ecosystem; D052918:Environmental Restoration and Remediation; D006540:Herbicides / Q000378:metabolism; D020582:Hyphomicrobium / Q000378:metabolism*; D008044:Linuron / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D059013:Microbial Consortia / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D003470:Culture Media; D006540:Herbicides; D012989:Soil Pollutants; D008044:Linuron; C014464:3,4-dichloroaniline; D002244:Carbon; D009584:Nitrogen