Dataset Information

Rate-Limiting Mass Transfer in Micropollutant Degradation Revealed by Isotope Fractionation in Chemostat.

ABSTRACT: Biodegradation of persistent micropollutants like pesticides often slows down at low concentrations (?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 TC1 in chemostat under four different dilution rates leading to 82, 62, 45, and 32 ?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 ?(C) = -5.36 ± 0.20‰ at 82 ?g/L to ?(C) = -2.32 ± 0.28‰ at 32 ?g/L. At 82 ?g/L ?(C) represented the full isotope effect of the enzyme reaction. At lower residual concentrations smaller ?(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 ?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.

SUBMITTER: Ehrl BN

PROVIDER: S-EPMC6365907 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Rate-Limiting Mass Transfer in Micropollutant Degradation Revealed by Isotope Fractionation in Chemostat.

Ehrl Benno N BN Kundu Kankana K Gharasoo Mehdi M Marozava Sviatlana S Elsner Martin M

Environmental science & technology 20181219 3

Biodegradation of persistent micropollutants like pesticides often slows down at low concentrations (μg/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 TC1 i ...[more]

PMID: 30514083

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Dataset Information

Rate-Limiting Mass Transfer in Micropollutant Degradation Revealed by Isotope Fractionation in Chemostat.

Publications

Rate-Limiting Mass Transfer in Micropollutant Degradation Revealed by Isotope Fractionation in Chemostat.

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