Synthesis and Characterization of Chitosan/Zinc Oxide Nanocomposite for Enhanced Applications as Antibacterial, Antifungal and Aflatoxin B1 Adsorption

The current study was designed to synthesize of chitosan (CS) by shrimp shells and grafted with zinc oxide nanoparticles (ZnO-NPs) in-situ precipitation method. The physical features of nanomaterials were studied using SEM, EDS, XRD, FTIR and UV-vis spectroscopy. The CS/Zn nanocomposite was crystalline, spherical with 12−18 nm in size. Nanocomposite's antibacterial and antifungal activity was evaluated against Staphylococcus aureus and Escherichia coli bacterial strains and Aspergillus flavus and A. parasiticus fungal strains, respectively. Additionally, the adsorbent's capacity of nanocomposite was examined with aflatoxin B₁ (AFB₁). Each nanomaterial shows the significant antibacterial activity against S. aureus and E. coli. The MI values for CS, Zn-NPs and CS/Zn nanocomposite were found to be 256, 128 and 32 µg/mL, respectively. Whereas, the growth of A. flavus, A. parasiticus and the AFB₁ production was inhibited at 5 mg/mL of CS/Zn nanocomposite. Adsorption capacities of ZnO-NPs, CS and CS/Zn nanocomposite were found to be 12.4, 64.5 and 150.4 ng/mg, respectively, as calculated by the Langmuir isotherm model. The thermodynamic and kinetic studies showed that the adsorption process is spontaneous, endothermic and followed the pseudo-second-order kinetic model. In conclusion, the synthesis of CS/Zn is simple, efficient, non-toxic, sustainable, energy-effective and useful as an alternative antibacterial, antifungal and as an AFB₁ detoxification agent in human and animal food.