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Ehrl, B. ; Kundu, K. ; Gharasoo, M. ; Marozava, S. ; Elsner, M.

Rate-limiting mass transfer in micropollutant degradation revealed by isotope fractionation in chemostat.

Environ. Sci. Technol. 53, 1197-1205 (2019)
Verlagsversion Forschungsdaten DOI
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
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
Korrespondenzautor
Schlagwörter Atrazine Catabolism Genes; Bioavailability Restrictions; Carbon; Growth; Biodegradation; Transformation; Limitation; Bacteria; Sulfate; Energy
ISSN (print) / ISBN 0013-936X
e-ISSN 1520-5851
Zeitschrift Environmental Science & Technology
Quellenangaben Band: 53, Heft: 3, Seiten: 1197-1205 Artikelnummer: , Supplement: ,
Verlag ACS
Verlagsort Washington, DC
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Institute of Groundwater Ecology (IGOE)