Physical factors controlling silver nanoparticles biosynthesis using actinomycetales bacterium βc1:MZ067956

Abstract

Biosynthesis of silver nanoparticles by actinomycetes is considered a bottom-up strategy that involves reducing silver atoms into AgNPs. In this experiment, the biosynthesis was carried out using 50% cell-free extract and 1.0 mM AgNO3. The physical factors that controlled biosyntheses, such as exposure time, pH, temperature, and light, were studied separately. The synthesis process was monitored by UV-Vis absorbance over 350-750 nm wavelength range. By increasing the exposure time, pH, and light, biosynthesized AgNPs were increased. The biosynthesized AgNPs at pH 5 representing unstable particles and at pH 9 representing stable particles were fully characterized using nanometrological techniques such as UV-Vis, FTIR, XRD, Zeta sizer, HR-TEM, and AFM. The obtained results displayed that the stable AgNPs have a spherical shape with a diameter ranging from 5 to 35 nm. This study confirmed the simplicity and applicability of the biosynthesis process with controlled physical conditions.