ABSTRACT

Nanotechnology is the science of synthesizing nanoparticles in nanometers (1-100nm). Nanoparticles (NPs) have found applications in diverse fields, necessitating the need for eco-friendly approaches to synthesize them. Biogenic synthesis is a clean, efficient, cost effective and non-toxic method applied in synthesis of NPs. This study was aimed at synthesis and characterisation of Ag NPs by cell-free enzymes of Providencia vermicola and it's application as an antimicrobial agent. Standard biological methods were followed for the synthesis of Ag NPs by cell-free enzymes of Providencia vermicola. The characterisation of synthesized NPs was carried out using UV-VIS Spectroscopy, FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction study), SEM and EDX (Scanning Electron Microscope and Energy Dispersive X-ray Spectroscopy). UV-Vis spectra showed the absorption peak formed at 400nm. FTIR showed an increase in transmittance at 2895cm^-1 and 3406cm^-1. The XRD spectrum exhibited peaks at 19.00° (210), 21.92° (122), 23.00° (111), 25.24° (200), 29.95° (231), 34.00° (142), 47.98° (241), 56.00° (220), 59.97° (311) and 63.98° (222) . The EDX spectrum showed that synthesized NPs had a particle size of 28.52 nm and consists of high amounts of Ag (67.65%), Carbon (16.65%) and Oxygen (9.84%). Synthesized NPs applied as an antimicrobial agent against clinical isolates showed the highest inhibition against Escherichia coli and Staphylococcus aureus. In conclusion, the synthesized Ag NPs from cell-free enzymes of Providencia vermicola was effective as an antimicrobial agent.