Green synthesis of zinc oxide nanoparticles using novel bacterium strain (Bacillus subtilis NH1-8) and their in vitro antibacterial and antibiofilm activities against Salmonellatyphimurium.

Zinc oxide nanoparticles (ZnO NPs) are used in a range of applications, including food packaging, preservation, and storage. In the current investigation, extracellular green synthesis of ZnO NPs through an simple, eco-friendly, and rapid approach using a novel bacterial strain (Bacillus subtilis NH1-8) was studied. To assess the morphological, optical, and structural properties of ZnO NPs, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and X-ray diffraction (XRD) techniques were carried out. In addition, disk diffusion, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) methods were performed to determine the antibacterial activity of ZnO NPs. The average size of biosynthesized ZnO NPs was 39 nm, exhibiting semi-spherical, which was confirmed by TEM analyses. The UV–vis spectroscopy exhibited the absorption peak at 200–800nm. The ZnO NPs have shown effective antimicrobial and antibiofilm activities against S. typhimurium. Thus, biosynthesized ZnO NPs could be exploited as a breakthrough technology in the surface coating of food containers and cans to minimize contamination by S. typhimurium. [Display omitted] • Salt Lake bacterium was used to biosynthesize zinc oxide nanoparticles. • The zinc oxide nanoparticles are found to be semi-spherical with an average size of 39 nm. • Differential action of zinc oxide nanoparticles is observed on a food-borne pathogen (S. typhimurium). • Cell constituents leakage increased in the zinc oxide nanoparticles treated bacterium. • The zinc oxide nanoparticles killed all the bacteria after 4 h. • Anti-biofilm activity of the nanoparticle on sub-lethal and lethal doses was considerable. [ABSTRACT FROM AUTHOR]