shown to be degraded in two soils collected from arid regions under aerobic
conditions while it was more persistent under anaerobic conditions, suggesting
that in terrestrial ecosystems its biodegradation is catalyzed by microorganisms
under aerobic conditions. The differences in naproxen half-lives were attributed to
specific soil types and microbial characteristics [38]. Studies from Grossberger et al.
[74] on agricultural soils irrigated with reclaimed water showed a rapid dissipation of
naproxen. Kinetics of dissipation were not enhanced in soils previously exposed to
this NSAID, suggesting that in this experiment the naproxen was co-metabolically
degraded.
Based on these studies, naproxen seems to be rapidly dissipated in soils where
under aerobic conditions it does not remain for long period of time. However, as
recurrent contaminant of reclaimed water that is repetitively applied in large volumes
to irrigate various crops, it may persist long enough to impact in soil living
microorganisms. Indeed, naproxen was found to irreversibly inhibit nitrite production in the ammonia oxidizing bacterium Nitrosomonas europeae following the loss
of its membrane integrity, which can potentially compromise nitrogen removal in
wastewater treatment plants [159]. Naproxen was also shown to change the abundance and the enzymatic activities of soil microorganisms inducing disturbances in
soil functions [160].
3.1.2 Ibuprofen
Ibuprofen is a nonprescription drug widely used for the treatment of pain, fever, and
rheumatic disorders. Ibuprofen is a chiral compound that contains two enantiomers,
the S-enantiomer (pharmacologically active) and the R-enantiomer (inactive) [161–
163]. During human metabolisms, R-ibuprofen undergoes chiral inversion, resulting
in S-ibuprofen, which is excreted in urine [164, 165]. This pharmacokinetics transformation to S-enantiomer is consistent with the observation of a selective enrichment of S-ibuprofen not only in wastewater influents [166, 167] and effluents [168]
but also in surface water [166, 169]. R-enantiomer biodegradation was reported in
aquatic systems [169, 170]. However, the depletion of S-enantiomer was shown in
wastewater effluents [167] and lake water microcosm spiked with ibuprofen [166]
suggesting that ibuprofen enantiomerization may also happen after its release in in
the environment.
The ability of both microbial communities [90] and pure microbial strain to
degrade ibuprofen has been widely reported [171]. The bacterium Nocardia.
sp. transforms ibuprofen to ibuprofenol and subsequently to the corresponding
acetate derivative [172]. Sphingomonas sp. uses ibuprofen as a sole carbon and
energy source via deoxygenation of the ring followed by meta-cleavage and catechol
formation catalyzed by enzymes encoded by ipfABDEF genes [107, 108, 171]. Bacillus thuringiensis and Serratia marcescens degrade ibuprofen more efficiently in the
presence of other carbons sources suggesting co-metabolic transformation [91, 92,
95]. Ibuprofen was also found to be degraded by white-rot fungi [153, 173] that
yielded a number of transformation products more toxic than the parent compound.
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conditions while it was more persistent under anaerobic conditions, suggesting
that in terrestrial ecosystems its biodegradation is catalyzed by microorganisms
under aerobic conditions. The differences in naproxen half-lives were attributed to
specific soil types and microbial characteristics [38]. Studies from Grossberger et al.
[74] on agricultural soils irrigated with reclaimed water showed a rapid dissipation of
naproxen. Kinetics of dissipation were not enhanced in soils previously exposed to
this NSAID, suggesting that in this experiment the naproxen was co-metabolically
degraded.
Based on these studies, naproxen seems to be rapidly dissipated in soils where
under aerobic conditions it does not remain for long period of time. However, as
recurrent contaminant of reclaimed water that is repetitively applied in large volumes
to irrigate various crops, it may persist long enough to impact in soil living
microorganisms. Indeed, naproxen was found to irreversibly inhibit nitrite production in the ammonia oxidizing bacterium Nitrosomonas europeae following the loss
of its membrane integrity, which can potentially compromise nitrogen removal in
wastewater treatment plants [159]. Naproxen was also shown to change the abundance and the enzymatic activities of soil microorganisms inducing disturbances in
soil functions [160].
3.1.2 Ibuprofen
Ibuprofen is a nonprescription drug widely used for the treatment of pain, fever, and
rheumatic disorders. Ibuprofen is a chiral compound that contains two enantiomers,
the S-enantiomer (pharmacologically active) and the R-enantiomer (inactive) [161–
163]. During human metabolisms, R-ibuprofen undergoes chiral inversion, resulting
in S-ibuprofen, which is excreted in urine [164, 165]. This pharmacokinetics transformation to S-enantiomer is consistent with the observation of a selective enrichment of S-ibuprofen not only in wastewater influents [166, 167] and effluents [168]
but also in surface water [166, 169]. R-enantiomer biodegradation was reported in
aquatic systems [169, 170]. However, the depletion of S-enantiomer was shown in
wastewater effluents [167] and lake water microcosm spiked with ibuprofen [166]
suggesting that ibuprofen enantiomerization may also happen after its release in in
the environment.
The ability of both microbial communities [90] and pure microbial strain to
degrade ibuprofen has been widely reported [171]. The bacterium Nocardia.
sp. transforms ibuprofen to ibuprofenol and subsequently to the corresponding
acetate derivative [172]. Sphingomonas sp. uses ibuprofen as a sole carbon and
energy source via deoxygenation of the ring followed by meta-cleavage and catechol
formation catalyzed by enzymes encoded by ipfABDEF genes [107, 108, 171]. Bacillus thuringiensis and Serratia marcescens degrade ibuprofen more efficiently in the
presence of other carbons sources suggesting co-metabolic transformation [91, 92,
95]. Ibuprofen was also found to be degraded by white-rot fungi [153, 173] that
yielded a number of transformation products more toxic than the parent compound.
272
S. Gallego and F. Martin-Laurent