Bacteria-mediated green synthesis of ZnO nanoparticles via different methods using a novel isolated from Howz Soltan Salt Lake (Qom, IRAN) and its antimicrobial, antibiofilm, and antioxidant activities

Abstract The current study showed a high metal tolerance of a novel Bacillus subtilis NH1-8 and its potential for Zinc oxide nanoparticles (ZnO NPs) synthesis. ZnO NPs were rapidly biosynthesize using and eco-friendly methods with a novel bacterium isolatedfrom Howz Soltan Salt Lake (Qom, IRAN). The effects of different synthesis methods and process parameters on particle yield were studied. As the best precursor salt, ZnSO4.H2O (0.1M) with a reaction time of 48 h, agitation rate of 150 rpm,physiological pH of 7.0, and optimal temperature of 30°C resulted in the synthesis of ZnO NPs with maximum yield. After optimization of growth conditions, ZnO NPs were studied using different techniques, including UV-Vis, FTIR, XRD, TEM, EDX, DLS, and zeta potential. The antifungal, antibacterial, and anti-biofilm activities of biosynthesized ZnO NPs were studied. The mechanism of antibacterial activity was evaluated on the basis of the leakage of nucleic acid from the cells and measuring protein. This study can be extended to develop a scalable and controlled process for the bacteriosynthesis of nanoparticles that can be used for diverse applications in industries.