Antimicrobial activity of silver nanoparticles biosynthesised by Rhodotorula sp. strain ATL72

In this study, the pink yeast Rhodotorula sp. strain ATL72 was isolated from salt marches near Mediterranean Sea, Egypt. From phylogenetic analysis, the isolated strain ATL72 was closely related to Rhodotorula bloemfonteinensis EU075187 by similarity of 40%. The biological synthesis of nanosilver (AgNPs) using the marine pink yeast Rhodotorula sp. strain ATL72 was established. The UV-Visible spectral analysis confirmed the synthesis of AgNPs showing a characteristic peak around 400-500 nm. TEM analysis not only confirmed the synthesis of AgNPs but also described the spherical and oval shaped nanoparticle besides size measurements ranged from 8.8 to 21.4 nm. The biosynthesized AgNPs showed a strong antimicrobial activity by causing a complete inhibition of growth for a wide range of Gram positive and Gram negative bacteria as well as fungi with low MIC value. In conclusion, the pink yeast Rhodotorula sp., strain ATL72 isolated from Egypt is a promising new biological source for the synthesis of silver nanoparticles having a potent antimicrobial activity against a wide range of pathogenic bacteria and fungi.