Synthesis and Characterization of Carboxylated Chitosan Nanocrystals from Shrimp Shell Biowaste using Reduced Chemical Volume: Structural and Antibacterial Properties

Shrimp shell biowaste used as a precursor effectively helps solve environmental problems related to waste management and provides a sustainable way to create valuable materials. This study investigates the synthesis and characterization of Carboxylated Chitosan Nanocrystals (ChsNCs) from shrimp shell biowaste while reducing the required chemical volumes. The process started with chitin synthesis from shrimp shells, followed by a controlled oxidation and carboxylation process to synthesize ChsNCs. The characterization of the synthesized ChsNCs began with the calculation of yield percentage to evaluate the efficiency of the synthesis process. Moreover, comprehensive characterization of synthesized ChsNC was conducted using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, X-ray Diffraction (XRD) spectroscopy, Thermal Analysis (TGA/DTA) and Fourier Transform Infrared (FTIR) spectroscopy to evaluate the morphological features, elemental composition, structural properties and thermal behaviour of the synthesized samples. The antibacterial properties of synthesized ChsNC were assessed against four bacterial strains using the well-diffusion method. The results show that the yield percentage and structural characterization confirmed the successful synthesis of ChsNC with reduced chemical volumes. Moreover, the synthesized ChsNC exhibits significant antibacterial activity, indicating larger inhibition zones at higher concentrations. The novelty of this research is the effective conversion of marine by-products of shrimp shell bio waste into ChsNCs with strong antibacterial properties by reducing the required chemical volumes. This study opens the way for broader applications of ChsNCs in biomedical and environmental fields, indicating a practical approach to developing biofunctional nanomaterials.