Green Synthesis of Magnesium Oxide Nanoparticles Using Probiotic Strain Lactobacillus Gasseri and Their Activity against Fungal Strains Isolated From Historical Manuscripts

Herein, a cheap, environmentally friendly, rapid, biocompatible, and reproducible green approach was used to synthesize magnesium oxide nanoparticles (MgO-NPs) by harnessing metabolites of probiotic bacteria Lactobacillus gasseri. The bacterial-mediated green synthesis of MgO-NPs was characterized by color change, UV-vis spectroscopy, transmission electron microscopy, energy dispersive X-ray, X-ray diffraction, and Fourier transform infrared spectroscopy. Data showed that the color of the cell-free filtrate was changed from colorless to white after mixing with metal precursor and exhibited maximum Surface Plasmon Resonance at 240 nm that confirm the successful formation of MgO-NPs. Moreover, the green synthesized MgO-NPs have a spherical shape with sizes in the ranges of 1-10 nm and are characterized by crystalline nature. The main components of the prepared sample were Mg and O with weight percentages of 42.3 and 36.92% and atomic percentages of 39.07 and 38.7% respectively. The biosynthesized MgO-NPs showed a high inhibitory effect compared to crude extract of probiotic bacteria stain, L. gasseri against ten fungal strains (Aspergillusustus AM4, Penicilliumcitrinum AM5, Penicilliumchrysogenum AM11, A. terreus AM12, P. citrinum AM13, P. citrinum AZ8, P. citrinum AZ9, A. nigerAZ11, P. chrysogenum AZ12, and P. chrysogenum AZ13) which isolated from deteriorated historical paper in a dose -dependent manner. The MIC values of synthesized MgO-NPs were 50-100 mu g mL-1 with a zone of inhibition of 12.3 +/- 0.6- 16.3 +/- 0.6 mm based on fungal strain.