Biogeochemical spatio‐temporal transformation of copper in Aspergillus niger colonies grown on malachite with different inorganic nitrogen sources

Abstract

Summary This work elucidates spatio‐temporal aspects of the biogeochemical transformation of copper mobilized from malachite (Cu2(CO3)(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.

Green-synthesized copper nanoparticles as a potential antifungal against plant pathogens

“…. 42 Subsequently, the dissolved copper ions produce ROS and oxidize the main components of the fungal cell walls such as glucan and chitin, which causes irreversible damage and disintegration of the cell wall. Once the cell walls are damaged, the Cu-NPs enter to the cells producing ROS that were detected by the DCFH-DA tests.…”

Biotransformation of struvite by Aspergillus niger: phosphate release and magnesium biomineralization as glushinskite

“…The pH of both solid and liquid media decreased because of acidification by A . niger , and this is particularly evident with ammonium‐containing media (Fomina et al ., ). The amount of phosphate (PO 4 3− ) released during the incubation period correlated with the decrease in pH for both natural and synthetic struvite.…”

“…Many fungi, including A. niger, are well known for lowering the pH of their surrounding environment (Burford et al, 2003;Fomina et al, 2005;Boswell et al, 2007;Gadd et al, 2012), and acidolysis was the prime mechanism for toxic metal mineral solubilization by various ericoid and ectomycorrhizal fungi (Fomina et al, 2004(Fomina et al, , 2005. The pH of both solid and liquid media decreased because of acidification by A. niger, and this is particularly evident with ammonium-containing media (Fomina et al, 2017). The amount of phosphate (PO 4 3− ) released during the incubation period correlated with the decrease in pH for both natural and synthetic struvite.…”

Monazite transformation into Ce‐ and La‐containing oxalates by Aspergillus niger

“…Other studies have shown that A. niger was able to solubilize and precipitate calcium from natural gypsum (CaSO 4 Á2H 2 O) as calcium oxalate (Gharieb et al, 1998). This fungal species is also capable of transforming more complex minerals such as malachite (Cu 2 (CO 3 )(OH) 2 ) into copper oxalate (Fomina et al, 2017). Another example showed that lead oxalate was precipitated by A. niger in Pb 2+ -containing media when supplemented with organic phosphate as the P source (Liang et al, 2016).…”