Pooja Choudhary, Sanjay Guleria, Shivani Sharma, Kavya Koshal, Kashyap Dubey, Gaurav Rajauria
In this work, we report an economical and environmentally friendly process for generating silver nanoparticles (AgNPs) from Lactobacillus plantarum culture supernatant. The results showed that the ideal parameters for synthesis of LP-AgNPs were 1 mM silver nitrate (AgNO3), mixed with culture filtrate in 1:1 ratio having the pH 11, with 3 h of incubation at 70℃. Functional groups present in the culture filtrate for stabilization and the reduction of silver ions were determined by FTIR analysis. FE-SEM and TEM studies showed that the LP-AgNPs have a spherical shape with a mean diameter of 8.45 nm. Energy-dispersive X-ray (EDX) analysis confirmed that the main constituent of the NPs was silver. The biofunctional properties of the synthesized nanoparticles were evaluated through DPPH radical scavenging activity, ABTS radical scavenging activity and FRAP assay for determining their antioxidant potential, whereas antimicrobial activity was also tested against three gram positive and three gram negative bacteria along with Aspergillus flavus, fungal strain. Significant catalytic degradation of four different dyes namely methylene blue (91.60% in 8 min), methyl orange (95.64% in 13 min), rhodamine B (93.68% in 11 min) and p-nitrophenol (94.18% in 22 min) was also shown by LP-AgNPs. Selective colorimetric responses for heavy metal ion detection, particularly Hg2 + ions, was also shown by LP-AgNPs with a lower detection limit of 331 nM.