Extracellular Biosynthesis of Gold Nanoparticles using Aspergillus niger – its Characterization and Stability

Abstract

The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials using microorganisms is gaining importance in the field of nanotechnology. In the present study, gold nanoparticles have been synthesized by reduction of aqueous gold ions using the culture supernatant of Aspergillus niger NCIM 616. The synthesis of the gold nanoparticles was monitored by UV-visible spectroscopy. The particles thereby obtained were characterized by UV, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The stability of the synthesized gold nanoparticles was analyzed by zeta potential measurement. Treatment of the fungal supernatant with aqueous Au + ions produced nanoparticles with an average particle size of 12.79 ± 5.61 nm. Different characterization studies showed that the extracellular enzyme secreted by Aspergillus niger NCIM 616 might be responsible for both formation and capping of the metal nanoparticles.

Combined efficacy of biologically synthesized silver nanoparticles and different antibiotics against multidrug-resistant bacteria

“…15 When the reaction mixture was incubated under dark conditions, the color of the liquid mixture changed from light yellowish brown to dark brown, and than black, subsequently, after 96 hours of reaction. (Figure 1).…”

“…[5][6][7][8][9][10][12][13][14][15] Compared with chemical and physical methods, biological synthesis of nanoparticles has proved to be free of any limitations associated with production of hazardous byproducts, and it is simple and cost effective in nature. 16,17 Microbiological synthesis can take place either intracellularly 7,18 or extracellularly.…”

“…16,17 Microbiological synthesis can take place either intracellularly 7,18 or extracellularly. 5,6,8,13,15 The mechanism underlying the synthesis of silver nanoparticles (AgNPs) by fungi can also be predicted; biosynthesis is basically associated with the reducing mechanism of the cellular components. In this reference involvement, the specific position of reductase enzymes was typically cited.…”

Bioinspired Magneto-optical Bacteria

“…An alternative approach to traditional synthetic chemistry is the biosynthesis of nanomaterials which employs natural organisms that reduce metal ions into stable nanoparticles. [9][10][11][12][13][14][15][16] Moreover, it should be borne in mind that there is ever increasing pressure to develop green, eco-friendly and economically-viable synthetic routes to nanomaterials. This has resulted in researchers turning towards biological organisms for inspiration.…”

“…[9][10][11][12][13][14][15][16] Biosynthesized nanoparticles usually exhibit enhanced stability and afford better control over morphology. Furthermore, bio-based fabrication has been shown to be reproducible and includes the possibility of synthesizing hydrophilic nanoparticles.…”