Original Articles: 2015 Vol: 7 Issue: 7
Biosynthesis of gold nanoparticles using Marine Streptomyces cyaneus and their antimicrobial, antioxidant and antitumor (in vitro) activities
The actinobacterial biosynthesis of gold nanoparticles (AuNPs) has been proposed as a cost effective environmental friendly alternative to chemical and physical methods. It is a reliable, important aspect of green chemistry approach that interconnects microbial biotechnology and nanobiotechnology. The target of the present investigation was to optimize the fermentation parameters controlling bioactive metabolites productivity by marine Streptomyces cyaneus, such as certain environmental conditions (different incubation periods, pH values, aeration, shaking speed and inoculum size ). Also, by supplying certain nutritional requirements (different carbon and nitrogen sources) for attaining the maximal antimicrobial activity yield by Streptomyces cyaneus against some pathogenic microorganisms. AuNPs were biosynthesized from chloroauric acid using cell free supernatant (as reducing and stabilizing agents), of Streptomyces cyaneus which grown in optimized fermentation medium, by heating or gamma irradiation processes. The synthesized AuNPs were characterized by UV-Vis spectroscopy, Dynamic Light Scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy, analysis which revealed morphology of spherical AuNPs within nano range from 6.5 nm to 20.0 nm with the main diameter of 12.63 nm by using gamma irradiation at 1 kGy. The biosynthesized AuNPs exhibited good antibacterial activity against some pathogenic Gram positive and Gram negative bacteria, also anti candida. AuNPs exhibited antioxidant activity and antitumor activity against human breast and liver carcinoma cells (in vitro). Finally, Gamma irradiation which induced AuNPs synthesis by cell-free supernatant of Streptomyces cyaneus with improved biomedical different applications is a simple, clean, economic and environmental friendly approach.