The inhibitory efficacy of silver nanoparticles produced from actinomycetes against certain types of pathogenic bacteria

Abstract

This study aimed to isolate actinomycetes from the soil of the industrial zone of Qasr Ahmed in the city of Misurata to test their ability to produce silver nanoparticles and determine their inhibitory efficacy against positive and negative tested bacteria of gram stain. 4 pure isolates of actinomycetes were isolated from soil samples. Two isolates showed (Streptomycessp. Act3 and Nocardia sp. Act4) their ability to produce silver nanoparticles that were detected by changing the color from pale yellow to brown after adding 1mM silver nitrate to the biomass filtrate, also determined the UV and visible UV absorption spectrum of the silver nanoparticles solution as a step to confirm the formation of silver nanoparticles and they are found along a 439 nm wavelength of the Streptomyces sp. Act3 and 436 nm for Nocardia sp. Act4,results of the inhibitory efficacy of silver nanoparticles using the method of disk diffusion showed that silver nanoparticles produced from the genus Streptomyces sp. Act3 was inhibiting activity against the tested bacteriaat a concentration of 100%, the diameter of the inhibition region against Escherichiacoli, Klebsiella sp. and Staphylococcusaureus 12, 11, 11 mm respectively, as for the genus Nocardia sp. Act4 at the same concentration, the diameter of the inhibition zone was reached against E. coli and Staph. aureus 10, 8 mm straight, versus Klebsiella sp. It did not give any inhibiting activity.