Characterization of biogenic Fe (III)‐binding exopolysaccharide nanoparticles produced by Ralstonia sp. SK03

Abstract

A new technological approach to nanoparticle synthesis is using microorganisms, such as bacteria, which have the ability to synthesize nontoxic nanoparticles with high biocompatibility. In addition, bacteria have strict control over size, structure, shape, and dimension of produced nanoparticles. In the present work, Fe (III)-binding exopolysaccharide (Fe-EPS) nanoparticles were biosynthesized by Ralstonia pickettii sp. SK03, a bacterium isolated from a mineral spring. 16S rRNA gene sequencing and biochemical tests were done for identification of the isolated bacterium. For the first time, critical biological and physicochemical properties of this iron oxide nanoparticle were characterized using Fourier Transform Infrared (FTIR) Spectroscopy, Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), Dynamic Light Scattering (DLS), Thermogravimetric analysis (TGA), X-ray crystallography (XRD), Atomic absorption spectroscopy (AAS), and cell viability assays (MTT assay). The characterization results showed that Fe-EPS nanoparticles were composed of spherical ferrihydrite nanoparticles (with a size range of 1.2-2 nm), trapped in a polysaccharide matrix. The TGA analysis demonstrated that Fe-EPS nanoparticles contained ∼25.2% polysaccharide. Therefore, this polysaccharide matrix showed a very low magnetic saturation value (0.25 emu/g) and a large negative charge of -93.8 mV. In addition, treatment of hepatocarcinoma cell line (Hep-G2) with 1-500 µg/mL concentrations of Fe-EPS nanoparticles caused 40% increase in the cell viability, which indicated that the biosynthesized nanoparticles were nontoxic and biocompatible. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1167-1176, 2018.

Controlled synthesis of iron oxyhydroxide (FeOOH) nanoparticles using secretory compounds from Chlorella vulgaris microalgae

“…Carbohydrate contents of the biosynthesized nanoparticles were reported to be 17 and 25 weight percent in the case of K. oxytoca and Ralstonia sp. synthesized nanoparticles, respectively [25,26]. Preparation of pure FeOOH nanoparticles without the addition of any biological compound or surface modification can be a significant advantage as these particles are suitable for any required functionalization.…”

“…Similar problems were found in the biosynthesized nanoparticles using Klebsiella oxytoca and Ralstonia sp. [25,26].…”

Optimization of reaction parameters for the green synthesis of zero valent iron nanoparticles using pine tree needles

“…Green synthesis has emerged as a promising approach in this regard. Due to employing natural compounds from plants or microorganisms, this method has significant advantages over the physical and chemical procedures [13][14][15][16][17][18]. However, there are still some difficulties with employing microorganisms for the synthesis of nanostructures [19,20].…”

Simulating the Formation and Dynamics of the Implicit Attitude; a Social Cognition Study

“…Till now, various microbial cells such as bacteria, fungi, diatoms, and microalgae are used to fabricate nanoparticles. The particles can be synthesized extracellularly or intracellularly [2,[4][5][6][7][8][9][10][11][12][13]. The major disadvantage of employing microbial cells in the synthesis of nanoparticles is that most of the employed organisms are pathogenic or opportunistic.…”