Sunlight Mediated Synthesis of Silver Nanoparticles by Bacillus sp and Its Antibacterial Property

Abstract

Development of antibiotic resistant strains in pathogenic bacteria is an alarming issue worldwide. Utilization of silver nanoparticles (AgNPs) could be possible way to address this concern but the conventional methods of producing AgNPs are toxic to the environment and expensive. This study demonstrates a cleaner and cheaper way of synthesizing AgNPs using silver tolerant bacterium and sunlight. Isolate I-NEUST was isolated from a local junkshop at Cabanatuan City, Nueva Ecija, Philippines was able to tolerate 3.5 mM of AgNO 3 and was found to be closely related to Bacilli species. AgNPs were successfully synthesized with a size of 63.8 nm and concentration of 4.44 mM. Silver nanoparticles exhibited considerable antibacterial activity against multidrug human pathogens. The effect was more distinct on Gram-negative bacterium Escherichia coli ATCC 25922. Nanoparticles also showed prominent activity on Gram-positive bacterium Staphylococcus aureus ATCC 25923. Hence, the present study demonstrates that biologically synthesized nanoparticle could be employed for developing antibacterial drug.