title: Spatial heterogeneity in degradation characteristics and microbial community composition of pesticide biopurification systems.
abstract: OBJECTIVE
  To investigate spatial and temporal differences in degradation characteristics and microbial community composition of pesticide biopurification systems.
  
  
  RESULTS
  Pilot-scale biofilters were supplemented with the potato-sprouting suppressant chloropropham. Two biofilters were inoculated with a chloropropham-degrading mixed culture, while the other two were not inoculated. Biodegradation rate, size and composition of the microbial community were monitored during 72 days at different biofilter depths. First of all, results showed that inoculation was not necessary to obtain efficient degradation although it shortens the biofilter's start-up period. Secondly, a higher biodegradation rate and chloropropham- and 3-chloroaniline-degrading microbial community size could be seen in the top part of the inoculated as well as the noninoculated biofilters. Finally, analysis of the microbial community composition shows that no clear spatial stratification of the microbial community could be found in any biofilter. However, the microbial diversity increases over time in all biofilters and on all biofilter depths, suggesting that during the time of the experiment, the biofilters develop a broad carrying capacity in which a genetically very diverse range of chloropropham- and 3-chloroaniline-degrading species can thrive.
  
  
  CONCLUSIONS
  In this study, a vertical gradient of the chloropropham- and 3-chloroaniline-degrading community composition, in terms of density and temporal and spatial diversity, was clearly established and was directly connected to a vertical gradient of chloropropham biodegradation activity.
  
  
  CONCLUSIONS
  The major part of degradation activity takes place in the top part of the biofilter, suggesting that it could be possible to use shorter biofilter reactors or higher loading rates to treat chloropropham waste streams, making this type of bioremediation technique economically more feasible.
authors.affiliation: Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium; Laboratory for Environmental Technology, Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Verhagen
authors.forename: C
authors.initials: C
authors.lastname: Destino
authors.forename: N
authors.initials: N
authors.lastname: Boon
authors.forename: L
authors.initials: L
authors.lastname: De Gelder
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D001419:Bacteria / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D002748:Chlorpropham / Q000378:metabolism; D010575:Pesticides / Q000378:metabolism*; D014873:Water Pollutants / Q000378:metabolism*; D018508:Water Purification
chemical_list: D000814:Aniline Compounds; D010575:Pesticides; D014873:Water Pollutants; D002748:Chlorpropham; C031392:3-chloroaniline
keywords: 3-chloroaniline; biodegradation; bioremediation; chloropropham; pesticide biopurification system