الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 109 |  |  |
| | | from | 109 | | |
Abstract
The pandemic of antibiotic resistance has become a serious threat to the therapeutic efficacy of the available antibiotics and their prescribed schedules. Antimicrobial resistance occurs when bacteria, viruses, fungi, and parasites change over time and no longer respond to medicines, making infections harder to treat and increasing the risk of disease spread, severe illness, and death. As a result of drug resistance, antibiotics and other antimicrobial medicines become ineffective, and infections become increasingly difficult or impossible to treat.
Nanomaterials were provided as an alternative solution for this problem. Green synthesis sources for synthesizing metal oxide nanoparticles are an interesting and expanding research area due to their potential antibacterial applications. This study represents an eco-friendly and biocompatible biological technique for producing manganese oxide nanoparticles (MnO NPs) with optimal efficiency, cost-effectiveness, size control, and no harmful chemicals used during biosynthesis. The MnO NPs successfully biosynthesized by reducing manganese sulfate (MnSO4.H2O) using the cell-free supernatant of Bacillus subtilis ATCC6633 by mixing 20 mL of 0.1 M MnSO4.H2O solution with 1 mL of B. subtilis crude metabolite at PH 8, 60 °C, and contentious stirring for 1 min. The dark brown colour indicates the biosynthesis of MnO NPs. The formation of MnO NPs was confirmed by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Zeta analysis, and transmission electron microscope (TEM). The biosynthesized MnO NPs displayed two absorption peaks at 285 and 353 nm. The FT-IR spectrum proved the existence of bacterial proteins during the biosynthesis of MnO NPs that might act as stabilizing agents. MnO NPs have a negative charge of -20.4 mV, according to Zeta analysis. The MnO NPs were nearly spherical in shape with a uniform size, according to the TEM results. The nanoparticles’ diameters were between 5.54 and 16.66 nm. Also, the mean particle sizes, in accordance with Scherrer’s formula, were found to be 21.35 nm, which confirmed the formation of NPs of small size.