Preparation and characterization of cellulose/ZnO nanoparticles extracted from peanut shells: effects on antibacterial and antifungal activities

This work aims to recycle peanut shells (residues) to use them as raw materials to produce nanocrystal cellulose. Two methods were used to synthesis zinc oxide nanoparticles (ZnO NPs) on cellulose nanocrystals (CNCs), in order to form the cellulose/zinc oxide nanoparticles (CNC/ZnO NPs). According to the results, Fourier transform infrared, X-ray diffraction, UV-visible, scanning electron microscopy, and energy-dispersive X-ray analysis characterized the CNC/ZnO NPs. UV-Visble spectra showed maximum absorption at 366 nm related to the zinc oxide. Fourier transform infrared spectra exhibit a weak peak at 432 cm(-1) attributed to zinc oxide vibration, confirming the formation of zinc oxide nanoparticles on cellulose nanocrystals. X-ray diffraction confirmed the crystalline nature of cellulose/zinc oxide nanoparticles with an average size between 20 and 28 nm. Scanning electron microscopy survey shows that the obtained nanoparticles have a lattice shape of rods surrounded by zinc oxide nanoparticles with a hexagonal wurtzite structure, as established by energy-dispersive X-ray analysis to confirm the presence of carbon, zinc, and oxygen. These cellulose/zinc oxide nanoparticles were tested against human pathogenic bacteria (Escherichia coli ATCC25922, Klebsiella pneumoniae ATCC 10,031, Staphylococcus aureus ATCC 25,923) and a fungus (Candida albicans ATCC 14,053). The obtained results revealed that these cellulose/zinc oxide nanoparticles synthesized from peanut shells have the effectiveness of an antibacterial activity against Gram ( +) and Gram ( -) bacteria together, and it shows excellent antifungal activity against Candida albicans; it seems to have an immense potential as the source of antibacterial and antifungal compounds. These results indicate that these newly fabricated cellulose/zinc oxide nanoparticle bio-nanocomposites by both methods contain potential antimicrobial components that may be of great benefit in the development of antimicrobial pharmaceutical industries and can be used as a treatment against various diseases caused by these organisms. It can also be employed in food systems as a novel preservative to inhibit microbial growth and repress the synthesis of exotoxins or control the growth of spoilage and disease-causing microorganisms.