Synthesis and Characterization of Antimicrobial Silver Nanoparticles by an Endophytic Fungus Isolated from Nyctanthes arbor-tristis

Biofabrication of metal nanoparticles is a cost-effective, one-step and ecofriendly technique. Cell filtrate of an endophytic fungus isolated from Nyctanthes arbor-tristis was challenged with 1 mM solution of AgNO3 for the silver nanoparticles (AgNPs) synthesis. A reduction of silver ions into AgNPs was observed by surface plasmon resonance at absorption maxima 422 nm. The average size of AgNPs was 35.05 nm. The maximum inhibition zones by AgNPs were 14 mm each against E. coli and Pseudomonas aeruginosa compared to AgNO3 solution used as control (10 mm and 9 mm). The fungus was identified as Phomopsis helianthi by the sequencing of ITS region of rDNA. This experiment demonstrates a single-step and ecofriendly method for biosynthesis of AgNPs and their usage as an antimicrobial agent.