Accessibility of humic-associated Fe to a microbial siderophore

Autor(en)

Keshia Kuhn, Patricia Maurice, E. Neubauer, T. Hofmann, F. Von Der Kammer

Abstrakt

Microorganisms in aerobic, circum-neutral environments are challenged to acquire sufficient nutrient Fe due to low solubilities of Fe oxides. To overcome this challenge, many aerobic microbes produce low molecular weight (MW) organic ligands, or siderophores, with extremely high Fe-binding affinities. This research expands the existing understanding of siderophore-mediated Fe acquisition from minerals by examining the effects of the siderophore desferrioxamine B (DFOB) on Fe removal from aquatic humic substances (XAD-8-isolated) and other organic matter (OM) isolates (reverse osmosis, RO; and "transphilic", XAD-4) from several rivers including the Suwannee River (GA, USA). Analysis of samples by asymmetrical flow field-flow fractionation (AsFlFFF) with in-line ICP-MS and UV-vis detectors showed that Fe was naturally abundant and primarily associated with intermediate to high MW OM. An excess of DFOB (relative to naturally present Fe) removed ∼75% of Fe and shifted the OM MW distribution to lower MWs, perhaps due to removal of "bridging" Fe, although additional mechanistic study of MW shifts is needed. Removal of other OM-associated metals (e.g., Al, Cu, Zn) by DFOB was minimal for all but a few samples. Fe bound to humic substances and other more "transphilic" organic components therefore should be considered readily bioavailable to aerobic, siderophore-producing microorganisms.

Organisation(en)

Externe Organisation(en)

University of Notre Dame

Journal

Environmental Science & Technology

Band

48

Seiten

1015-1022

Anzahl der Seiten

8

ISSN

0013-936X

DOI

https://doi.org/10.1021/es404186v

Publikationsdatum

01-2014

Peer-reviewed

Ja

ÖFOS 2012

104002 Analytische Chemie, 104023 Umweltchemie, 105904 Umweltforschung

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3c50d4ff-f9cc-4549-9ec3-cf5cecef8ea3