Open AccessAerobic biodegradation of chiral phenoxyalkanoic acid derivatives during incubations with activated sludge
Author(s) -
Zipper Christian,
Fleischmann Thomas,
Kohler HansPeter E.
Publication year - 1999
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1999.tb00611.x
Subject(s) - propanoic acid , enantiomer , biodegradation , incubation , racemic mixture , chemistry , stereochemistry , chromatography , biology , organic chemistry , biochemistry
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.