A rapid method to screen degradation ability in chlorophenoxyalkanoic acid herbicide-degrading bacteria.
OBJECTIVE
An agar medium containing a range of related chlorophenoxyalkanoic acid herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), racemic mecoprop, (R)-mecoprop and racemic 2,4-DP (2-(2,4-dichlorophenoxy) propionic acid) was developed to assess the catabolic activity of a range of degradative strains.


RESULTS
The medium was previously developed containing 2,4-D as a carbon source to visualise degradation by the production of dark violet bacterial colonies. Strains isolated on mecoprop were able to degrade 2,4-D, MCPA, racemic mecoprop, (R)-mecoprop and racemic 2,4-DP, whereas the 2,4-D-enriched strains were limited to 2,4-D and MCPA as carbon sources. Sphingomonas sp. TFD44 solely degraded the dichlorinated compounds, 2,4-D, racemic 2,4-DP and 2,4-DB (2,4-dichlorophenoxybutyric acid). However, Sphingomonas sp. AW5, originally isolated on 2,4,5-T, was the only strain to degrade the phenoxybutyric compound MCPB (4-chloro-2-methylphenoxybutyric acid).


CONCLUSIONS
This medium has proved to be a very effective and rapid method for screening herbicide degradation by bacterial strains.


CONCLUSIONS
This method reduces the problem of assessing the biodegradability of this family of compounds to an achievable level.
Smejkal
C W
CW
School of Biological Sciences, University of Exeter, UK. C.W.Smejkal@exeter.ac.uk
Vallaeys
T
T
Burton
S K
SK
Lappin-Scott
H M
HM
D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000378:metabolism*; D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives*; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003470:Culture Media; D006540:Herbicides / Q000378:metabolism*
D003470:Culture Media; D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid; C008340:mecoprop; D015085:2,4,5-Trichlorophenoxyacetic Acid; D008456:2-Methyl-4-chlorophenoxyacetic Acid; C010571:dichlorprop