2,4-Dichlorophenoxyacetic acid (2,4-D) biodegradation in river sediments of Northeast-Scotland and its effect on the microbial communities (PLFA and DGGE).
A bench-scale study was conducted to investigate 2,4-D biodegradation rates at different concentrations (10, 100 and 1000 microg per gram of dry weight) in distinct sediments samples collected on the River Ythan, Northeast-Scotland. Mineralisation of 14C 2,4-D occurred mostly within 30 days for all tested concentrations with a degradation rate ranging from 5 to 750 microg d(-1). Biodegradation rates were affected by the biological and biochemical characteristics of the indigenous microbial community in the studied sediments rather than factors such as compound bioavailability and/or toxicity. PLFA-profiling provided evidences of the effect of 2,4-D amendments on the microbial communities and DGGE-profiling showed changes in the genetic potential of the microbial populations which might affect metabolic characteristics of the sediment. PLFAs biomarkers suggested that the pathway of alpha-ketoglutarate-dependent dioxygenase was the main route of 2,4-D biodegradation. This pathway is commonly found in microorganisms of the beta-subdivision of proteobacteria.
Dep. De Hidráulica e Saneamento, University of São Paulo (EESC/USP), Av. Trabalhador, São-Carlense 400, 13566-590 São Carlos, SP, Brazil. chinalia@htomail.com
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Chinalia
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Killham
D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D019015:Geologic Sediments; D012606:Scotland; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D014874:Water Pollutants, Chemical; D015084:2,4-Dichlorophenoxyacetic Acid