Characterization of novel linuron-mineralizing bacterial consortia enriched from long-term linuron-treated agricultural soils.
Linuron-mineralizing cultures were enriched from two linuron-treated agricultural soils in the presence and absence of a solid support. The cultures contained linuron-degrading bacteria, which coexisted with bacteria degrading either 3,4-dichloroaniline (3,4-DCA) or N,O-dimethylhydroxylamine (N,O-DMHA), two common metabolites in the linuron degradation pathway. For one soil, the presence of a solid support enriched for linuron-degrading strains phylogenetically related to but different from those enriched without support. Most linuron-degrading consortium members were identified as Variovorax, but a Hydrogenophaga and an Achromobacter strain capable of linuron degradation were also obtained. Several of the linuron-degrading isolates also degraded 3,4-DCA. Isolates that degraded 3,4-DCA but not linuron belonged to the genera Variovorax, Cupriavidus and Afipia. Hyphomicrobium spp. were involved in the metabolism of N,O-DMHA. Whereas several isolates degraded linuron independently, more efficient degradation was achieved by combining linuron and 3,4-DCA-degraders or by adding casamino acids. These data suggest that (1) linuron degradation is performed by a group of metabolically interacting bacteria rather than by individual strains, (2) there are other genera in addition to Variovorax that degrade linuron beyond 3,4-DCA, (3) linuron-degrading consortia of different origins have a similar composition, and (4) interactions between consortium members can be complex and can involve exchange of both metabolites and other nutrients.
Breugelmans
Philip
P
Division Soil and Water Management, Catholic University of Leuven, Leuven, Belgium.
D'Huys
Pieter-Jan
PJ
De Mot
René
R
Springael
Dirk
D
D000383:Agriculture; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D042621:Comamonadaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D017753:Ecosystem; D006540:Herbicides / Q000378:metabolism*; D008044:Linuron / Q000378:metabolism*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D006540:Herbicides; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D008044:Linuron