Synthesis of Biodegradable Nanocomposite–Based Chitosan/Ag NPs for Food Packaging

The most growing concern nowadays is plastic pollution because plastic can take hundreds of years to break down and is not biodegradable. So, it has led to attention towards developing biodegradable and environmentally friendly packaging. Two biofilm-forming bacterial strains were isolated and identified up to the species level. The silver-chitosan composite film was prepared, and the film’s mechanical, structural, and antibacterial properties; potential application; and biodegradation were analyzed. Via 16 s rRNA gene sequencing, two strains were identified as Priestia megaterium (PQ269828) and Klebsiella
sp. (MN631045). The UV–Vis absorption peak at 413 nm confirmed the formation of silver nanoparticles (AgNPs), and the Fourier transform infrared (FTIR) peak at 1647 cm−1 showed the carbonyl (C=O) stretch of the NH₂ group. Scanning electron microscopy (SEM) showed aggregated nanostructure. Zeta potential results showed low charge (0.0263 mV) for the particles, and the film showed low moisture retention, solubility, and swelling due to the cross-linking effect of AgNPs. Both strains showed promising antibacterial activity (up to 19.4±0.4 mm zone of inhibition (ZOI)) against biofilm-forming Priestia megaterium and Klebsiella sp. and pathogenic Staphylococcus aureus and Escherichia coli (up to 28.6±0.5 mm ZOI), the results were statistically highly significant (P±0.000). The films also showed promising results in enhancing the shelf life of tomatoes as well as rapid biodegradability. The results suggested that the silver-chitosan nanocomposite films can be a potential alternative to plastic packaging, reducing pollution, and enhancing the shelf life of food products.