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Biogeochemical spatio‐temporal transformation of copper in A spergillus niger colonies grown on malachite with different inorganic nitrogen sources
Author(s) -
Fomina Marina,
Bowen Andrew D.,
Charnock John M.,
Podgorsky Valentin S.,
Gadd Geoffrey M.
Publication year - 2017
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13664
Subject(s) - malachite , copper , oxalate , biogeochemical cycle , biology , ammonium , aspergillus niger , nitrogen , malachite green , nitrate , environmental chemistry , nuclear chemistry , botany , inorganic chemistry , chemistry , biochemistry , ecology , organic chemistry , adsorption
Summary This work elucidates spatio‐temporal aspects of the biogeochemical transformation of copper mobilized from malachite (Cu 2 (CO 3 )(OH) 2 ) and bioaccumulated within Aspergillus niger colonies when grown on different inorganic nitrogen sources. It was shown that the use of either ammonium or nitrate determined how copper was distributed within the colony and its microenvironment and the copper oxidation state and succession of copper coordinating ligands within the biomass. Nitrate‐grown colonies yielded ∼1.7× more biomass, bioaccumulated ∼7× less copper, excreted ∼1.9× more oxalate and produced ∼1.75× less water‐soluble copper in the medium in contrast to ammonium‐grown colonies. Microfocus X‐ray absorption spectroscopy revealed that as the mycelium matured, bioaccumulated copper was transformed from less stable and more toxic Cu(I) into less toxic Cu(II) which was coordinated predominantly by phosphate/malate ligands. With time, a shift to oxalate coordination of bioaccumulated copper occurred in the central older region of ammonium‐grown colonies.