Abstract
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► The mangrove isolate Streptomyces sp. BDUKAS10 was characterized at morphological, biochemical and molecular level. ► Streptomyces sp. BDUKAS10 was exploited for the extracellular biosynthesis of AgNPs. ► Biosynthesized AgNPs was characterized using UV, FTIR, EDAX and TEM. ► Comparative antimicrobial activity was evaluated between cell free supernatant and microbe derived AgNPs.
Biosynthesis has led to the development of various biomimetic approaches for the fabrication of nanoscale materials. The present study reveals a unique procedure for the biosynthesis of bactericidal silver nanoparticles (AgNPs) using a novel Streptomyces sp. BDUKAS10, an isolate of mangrove sediment. Aqueous silver nitrate (AgNO3) solution was treated with cell free supernatant (CFS) of the isolate to synthesize bactericidal silver nanoparticles. Initial characterization was performed by visual observation for color change to intense brown color. UV–visible spectrophotometry (UV–vis) for measuring surface plasmon resonance indicated a maximum absorption peak at 441nm. Fourier Transform Infrared Spectroscopy (FTIR) analysis provides evidence for proteins as possible reducing, and capping agents. Energy dispersive X-ray (EDAX) spectroscopy analysis showed elemental silver as major signal. Transmission Electron Microscopy (TEM) study indicated spherical silver nanoparticles in the size range of 21–48nm. Compared to the CFS, the biosynthesized AgNPs exemplified superior bactericidal efficacy towards the tested bacterial strains. Results from this study suggested that Streptomyces sp. BDUKAS10 can be advantageous for the synthesis of AgNPs by extracellular method in the view of sustainable and ecofriendly approach.