Green biosynthesis of silver nanoparticles using novel endophytic Rothia endophytica: Characterization and anticandidal activity

Nanotechnology has the ability to improve human health with novel tools for the treatment of diseases. In this study, Rothia endophytica is a novel endophytic bacterial strain isolated from healthy Maize roots for biosynthesis of silver nanoparticles (Ag-NPs). Rothia endophytica was found to be a good producer for Ag-NPswith a novel cubic shape. The surface plasmon excitation of biosynthesized Ag-NPs appeared at 410 nm according to UV–visible spectroscopy analysis. Transmission electron microscopy (TEM) showed well-dispersed cubic Ag-NPs with sizes ranged from 47 nm to 72 nm. The X-ray diffraction (XRD) pattern revealed face-centered cubic nano-crystal structured Ag-NPs. FTIR spectral analysis demonstrated the existence of functional groups of strain-biomolecules that could be responsible for fabrication, capping and stabilizing Ag-NPs. Our results showed a significant antifungal activity of biosynthesized Ag-NPsagainst Candida albicans (C. albicans) with MIC and MBC at 62.5 and 125 μg/mL, respectively. AgNPs-treated C. albicans revealed elevation of membrane lipid peroxidation, reducing sugars and total proteins in a time-dependent manner, causing membrane leakage and eventually reducing cell viability. Ultrastructure changes observed in Ag-NPs-treated C. albicans demonstrated the permeabilization of the cell wall and subsequent disruption of the structural layers of the outer fungal cell wall in a time-dependent manner. In conclusion, our data suggest that novel biosynthesized Ag-NPs is a promising anticandidal agent to combat and reduce human pathogenic Candida.