Biomineralization of gold by Mucor plumbeus: The progress in understanding the mechanism of nanoparticles’ formation

Abstract

This contribution describes the deposition of gold nanoparticles by microbial reduction of Au(III) ions using the mycelium of Mucor plumbeus. Biosorption as the major mechanism of Au(III) ions binding by the fungal cells and the reduction of them to the form of Au(0) on/in the cell wall, followed by the transportation of the synthesized gold nanoparticles to the cytoplasm, is postulated. The probable mechanism behind the reduction of Au(III) ions is discussed, leading to the conclusion that this process is nonenzymatic one. Chitosan of the fungal cell wall is most likely to be the major molecule involved in biomineralization of gold by the mycelium of M. plumbeus. Separation of gold nanoparticles from the cells has been carried out by the ultrasonic disintegration and the obtained nanostructures were characterized by UV-vis spectroscopy and transmission electron micrograph analysis. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1381-1392, 2017.

Forced Biomineralization: A Review

“…Gold ions bind on the oppositely charged mycelia of fungus Rhizopus oryzae through electrostatic interaction with phosphoproteins and are then reduced to Au (I) species due to the high redox potential of Au (III) [59,60]. Various biomacromolecules have been reported to show templating activity with respect to gold biomineralization in different microorganisms [54]. For example, the nonribosomal peptide of Delftia acidovorans, termed delftibactin A (Figure 2a), is responsible for chelating soluble Au 3+ and directly precipitating it as a complex, or by binding and reducing gold through oxidative decarboxylation before chelating a second Au 3+ ion and precipitating a complex (Figure 2c) [55].…”

“…Various biomacromolecules have been reported to show templating activity with respect to gold biomineralization in different microorganisms [ 54 ]. For example, the non-ribosomal peptide of Delftia acidovorans , termed delftibactin A ( Figure 2 a), is responsible for chelating soluble Au 3+ and directly precipitating it as a complex, or by binding and reducing gold through oxidative decarboxylation before chelating a second Au 3+ ion and precipitating a complex ( Figure 2 c) [ 55 ].…”