Green synthesis of silver nanoparticles using Bacillus cereus, an endophytic bacterium isolated from Garcinia xanthochymus

Ecofriendly synthesis of nanoparticles is viewed as an alternative to the chemical method which initiated the use of microbes like bacteria and fungi in their synthesis. The current study uses the endophytic bacterium Bacillus cereus isolated from the Garcinia xanthochymus to synthesize the silver nanoparticles (AgNPs). The AgNPs were synthesized by reduction of silver nitrate (AgNO₃) solution by the endophytic bacterium after incubation for 3-5 days at room temperature. The synthesis was initially observed by colour change from pale white to brown which was confirmed by UV -Vis spectroscopy. The AgNPs were further characterized using FTIR, SEM-EDAX. The synthesized nanoparticles were found to be spherical with the size in the range of 40 nm. The energy-dispersive spectroscopy of the nanoparticle dispersion confirmed the presence of elemental silver. The AgNPs were found to have antibacterial activity against a few pathogenic bacteria like Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.