This study focuses on the synthesis of aluminum oxide nanoparticles (AlO-NPs) hydrogel through in situ method and formation of biopolymer nanocomposite film. UV-Vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), particle size analyzer, and energy dispersive X-ray spectrum were performed for the characterization of AlO-NPs. TEM micrograph demonstrates the presence of AlO-NPs in the range of 50-100 nm in the hydrogel network made from sugarcane bagasse carbo-xymethyl cellulose (SB-CMC) and synthetic carboxymethyl cellulose (CMC). The successful absorptions peak at 210 nm while conducting UV-Vis spectroscopy suggests existence of AlO-NPs. The antibacterial properties of AlO-NPs were analyzed using the disc plate diffusion technique against Gram-negative bacteria:Escherichia coli (ATCC 433); and Gram-positive bacteria: Bacillus subtilis (ATCC 1688). AlO-NPs present in CMCs films reduce moisture content, solubility; elongation at break and increases films' tensile strength.