Rate-limiting mass transfer in micropollutant degradation revealed by isotope fractionation in chemostat.
Environ. Sci. Technol. 53, 1197-1205 (2019)
Biodegradation of persistent micropollutants like pesticides often slows down at low concentrations (mu g/L) in the environment. Mass transfer limitations or physiological adaptation are debated to be responsible. Although promising, evidence from compound-specific isotope fractionation analysis (CSIA) remains unexplored for bacteria adapted to this low concentration regime. We accomplished CSIA for degradation of a persistent pesticide, atrazine, during cultivation of Arthrobacter aurescens TCl in chemostat under four different dilution rates leading to 82, 62, 45, and 32 mu g/L residual atrazine concentrations. Isotope analysis of atrazine in chemostat experiments with whole cells revealed a drastic decrease in isotope fractionation with declining residual substrate concentration from epsilon(C) = -5.36 +/- 0.20 parts per thousand at 82 mu g/L to epsilon(C) = -2.32 +/- 0.28 parts per thousand at 32 mu g/L. At 82 mu g/L epsilon(C) represented the full isotope effect of the enzyme reaction. At lower residual concentrations smaller epsilon(C) indicated that this isotope effect was masked indicating that mass transfer across the cell membrane became rate-limiting. This onset of mass transfer limitation appeared in a narrow concentration range corresponding to about 0.7 mu M assimilable carbon. Concomitant changes in cell morphology highlight the opportunity to study the role of this onset of mass transfer limitation on the physiological level in cells adapted to low concentrations.
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Typ der Hochschulschrift
Herausgeber
Schlagwörter
Atrazine Catabolism Genes; Bioavailability Restrictions; Carbon; Growth; Biodegradation; Transformation; Limitation; Bacteria; Sulfate; Energy
Keywords plus
Sprache
englisch
Veröffentlichungsjahr
2019
Prepublished im Jahr
2018
HGF-Berichtsjahr
2018
ISSN (print) / ISBN
0013-936X
e-ISSN
1520-5851
ISBN
Bandtitel
Konferenztitel
Konferzenzdatum
Konferenzort
Konferenzband
Quellenangaben
Band: 53,
Heft: 3,
Seiten: 1197-1205
Artikelnummer: ,
Supplement: ,
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Verlag
ACS
Verlagsort
Washington, DC
Tag d. mündl. Prüfung
0000-00-00
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Gutachter
Prüfer
Topic
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Veröffentlichungsdatum
0000-00-00
Anmeldedatum
0000-00-00
Anmelder/Inhaber
weitere Inhaber
Anmeldeland
Priorität
Begutachtungsstatus
Peer reviewed
POF Topic(s)
20403 - Sustainable Water Management
Forschungsfeld(er)
Environmental Sciences
PSP-Element(e)
G-504390-001
Förderungen
Copyright
Erfassungsdatum
2019-01-10