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Defining lower limits of biodegradation: atrazine degradation regulated by mass transfer and maintenance demand in Arthrobacter aurescens TC1.

ISME J. 13, 2236-2251 (2019)
Verlagsversion Forschungsdaten DOI
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
( )Exploring adaptive strategies by which microorganisms function and survive in low-energy natural environments remains a grand goal of microbiology, and may help address a prime challenge of the 21st century: degradation of man-made chemicals at low concentrations ("micropollutants"). Here we explore physiological adaptation and maintenance energy requirements of a herbicide (atrazine)-degrading microorganism (Arthrobacter aurescens TC1) while concomitantly observing mass transfer limitations directly by compound-specific isotope fractionation analysis. Chemostat-based growth triggered the onset of mass transfer limitation at residual concentrations of 30 mu g L-1 of atrazine with a bacterial population doubling time (t(d)) of 14 days, whereas exacerbated energy limitation was induced by retentostat-based near-zero growth (t(d) = 265 days) at 12 +/- 3 mu g L-1 residual concentration. Retentostat cultivation resulted in (i) complete mass transfer limitation evidenced by the disappearance of isotope fractionation (epsilon C-13 = -0.45%o +/- 0.36 parts per thousand) and (ii) a twofold decrease in maintenance energy requirement compared with chemostat cultivation. Proteomics revealed that retentostat and chemostat cultivation under mass transfer limitation share low protein turnover and expression of stress-related proteins. Mass transfer limitation effectuated slow-down of metabolism in retentostats and a transition from growth phase to maintenance phase indicating a limit of similar or equal to 10 mu g L-1 for long-term atrazine degradation. Further studies on other ecosystem-relevant microorganisms will substantiate the general applicability of our finding that mass transfer limitation serves as a trigger for physiological adaptation, which subsequently defines a lower limit of biodegradation.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Schlagwörter S-triazine Ring; Geobacter-metallireducens; Isotope Fractionation; Label-free; Growth; Limitation; Responses; Energy; Transformation; Physiology
ISSN (print) / ISBN 1751-7362
e-ISSN 1751-7370
Zeitschrift ISME Journal
Quellenangaben Band: 13, Heft: 9, Seiten: 2236-2251 Artikelnummer: , Supplement: ,
Verlag Nature Publishing Group
Verlagsort Macmillan Building, 4 Crinan St, London N1 9xw, England
Begutachtungsstatus Peer reviewed