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Aerobic biodegradation of chiral phenoxyalkanoic acid derivatives during incubations with activated sludge (1999)

Zipper, Christian ; Fleischmann, Thomas ; Kohler, Hans-Peter E.

Oxford, UK : Blackwell Publishing Ltd

FEMS microbiology ecology 29 (1999), S. 0

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ISSN: 1574-6941

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: The aerobic biodegradation of racemic mixtures of five chiral phenoxyalkanoic acids was studied according to a biodegradation test that was complemented with enantiomer-specific analysis. Both enantiomers of (RS)-2-phenoxypropanoic acid, (RS)-2-(3-chlorophenoxy)propanoic acid, and (RS)-2-(4-chlorophenoxy)propanoic acid, were completely degraded within 25 days when aerobically incubated with activated sludge. During incubations of (RS)-2-phenoxypropanoic acid, the (R) enantiomer was degraded before the (S) enantiomer, whereas during incubations of (RS)-2-(3-chlorophenoxy)propanoic acid the (S) enantiomer was preferentially degraded. The (R) enantiomer of (RS)-2-(2-chlorophenoxy)propanoic acid was removed after 24 days while only 30% of the (S) enantiomer was degraded within 47 days of incubation. (RS)-2-(2,4,5-Trichlorophenoxy)propanoic acid was the most persistent of all the racemic mixtures tested. After 47 days, the concentration of the (S) enantiomer was nearly unchanged, and the concentration of (R)-2-(2,4,5-trichlorophenoxy)propanoic acid had decreased only by about 40%. The differences observed in the length of the lag phases and in the degradation rates of individual enantiomers can lead to accumulations of the more recalcitrant enantiomer in aquatic or terrestrial ecosystems.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1574-6941.1999.tb00611.x

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Fate of the herbicides mecoprop, dichlorprop, and 2,4-D in aerobic and anaerobic sewage sludge as determined by laboratory batch studies and enantiomer-specific analysis (1999)

Zipper, Christian ; Bolliger, Christoff ; Fleischmann, Thomas ; [et al.]

Springer

Biodegradation 10 (1999), S. 271-278

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ISSN: 1572-9729

Keywords: chirality ; 2,4-D ; dichlorprop ; herbicide biodegradation ; mecoprop ; phenoxyalkanoic acid herbicides

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Aerobic degradation experiments with the racemic mixtures of mecoprop and dichlorprop revealed that activated sludge collected from the aeration tank of a municipal waste water treatment plant degraded both enantiomers of mecoprop and dichlorprop within 7 days, albeit in an enantioselective manner; the (S) enantiomers were preferentially degraded. Mecoprop, dichlorprop, and 2,4-D were completely metabolized under aerobic conditions, as shown by the 86–98% elimination of dissolved organic carbon. Under anaerobic conditions, the concentration of 2,4-D decreased exponentially with a first-order reaction rate constant of 0.24 per day and without a lag-phase. After an incubation time of 17 days, 2,4-D was completely removed. 2,4-Dichlorophenol was the main metabolite of anaerobic 2,4-D degradation; only traces of 4-chlorophenol were detected. In contrast, the chiral phenoxypropionic acid herbicides mecoprop and dichlorprop persisted under anaerobic conditions during 49 days of incubation.