Lactobacillus Mediated Synthesis of Silver Oxide Nanoparticles

Abstract

The ability of prokaryotic microorganisms to reduce the inorganic metals has opened up an exciting eco-friendly approach towards the development of natural 'nano-factories'. However, a number of issues have to be addressed from the nanotechnological and microbiological point of view before such a biosynthesis approach can compete with the existing physical and chemical methods. This report investigates the synthesis of silver oxide nanoparticles using Lactobacillus mindensis, isolated using fixer solution from an X-ray photographic laboratory. Nanoparticles obtained were characterized by means of UV-vis spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The UV-vis spectrum shows the absorbance maximum at 430 nm, which is a characteristic of surface plasmon resonance of silver. Further, the presence of stable nanoparticles in the range of 2-20 nm was determined using TEM analysis. Silver nanoparticles in the form of silver oxide were confirmed in the XRD study. In conclusion, Lactobacillus mindensis serves as a promising candidate in the quest to synthesize silver oxide nanoparticles through green chemistry.

A novel approach for the biosynthesis of silver oxide nanoparticles using aqueous leaf extract ofCallistemon lanceolatus(Myrtaceae) and their therapeutic potential

“…Major peaks were obtained at positions that conform to the Miller indices (hkl) of silver oxide (100, 110, 111, 200, 211, 220, 310 and 311). [36,39] XRD analysis, therefore, confirms the face-centred cubic (FCC) configuration of biosynthesised Ag 2 O nanoparticles. The mean particle diameter of silver oxide nanoparticles was calculated from the XRD pattern using the Scherrer equation:…”

“…Both these peaks match those obtained in the synthesis of Ag2O nanoparticles through other natural methods. [39] The formation of Ag 2 O nanoparticles could be mediated by the presence of polyphenols present in the leaf extract. These contribute the OH-group to Ag C and result in the formation of AgOH, which is then oxidised to Ag 2 O. AgOH is highly unstable because of the high electronegativity of Ag C and the size difference between Ag C and OH ¡ ions.…”

“…The pellet was washed thrice using deionised water to completely remove unwanted surface impurities from the nanoparticles. The pellets were dried on a Petri dish in a hot air oven at 60 C. [39,49] After drying completely, the powder was scraped off to yield silver oxide nanoparticles. These were stored in Eppendorf tubes at room temperature for further usage and analysis.…”

“…A biological route for synthesis of silver oxide nanoparticles using Lactobacillus extract has also been explored recently. [39] Synthesis of silver oxide nanoparticles using polyethylene glycol (PEG) has also been discussed. [40] However, plant extract mediated synthesis of silver oxide nanoparticles is still unknown.…”

Evaluation of the effect of indigenous mycogenic silver nanoparticles on soil exo-enzymes in barite mine contaminated soils

“…In addition, aggregations of NPs may have an effect on their biological behavior as well. Many microorganisms, plant extracts and fungi have been shown to produce NPs through biological pathways (Abou ElNour et al 2010;Mohanpuria et al 2008;Ghorbani et al 2011;Popescu et al 2010;Dhoondia and Chakraborty 2012;Sastry et al 2003;Prasad and Elumalai 2011). The use of fungi in the synthesis of metallic NPs is relatively exciting, and was identified as one of the potential microorganisms as they secrete significant amounts of enzymes that are easily handled at the laboratory level.…”