<![CDATA[This study aims to optimize the stepwise chemical process for the synthesis of nanochitosan from shrimp shell waste by varying the concentration of sodium hypochlorite (NaOCl) and the bleaching time, as well as to evaluate the characteristics of the resulting product. The synthesis process includes demineralization using HCl, deproteinization using NaOH, bleaching with varying NaOCl concentrations of 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% at bleaching times of 5, 10, 15, 30, and 60 minutes, followed by deacetylation to produce chitosan. Nanochitosan was then synthesized using the ionic gelation method with the addition of tripolyphosphate (TPP). Characterization was performed through yield testing, antimicrobial activity testing, Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM). The results showed that the highest yield was obtained with a 0.1% NaOCl treatment for 5 minutes at 93.33%, while the highest antimicrobial activity was observed at a 0.3% NaOCl concentration for 15 minutes, with an inhibition zone diameter of 11.40 mm. Increasing the NaOCl concentration and bleaching duration tended to reduce the yield due to partial degradation of the chitosan polymer structure. FTIR analysis revealed the presence of functional groups characteristic of nanochitosan, namely hydroxyl (O–H) and amine (N–H) groups, as well as C–O and C–N bonds, indicating the success of the nanochitosan synthesis process. SEM characterization of the best sample revealed a relatively homogeneous surface morphology with a finer particle structure. Based on the research results, treatment with 0.3% NaOCl for a bleaching time of 15 minutes is the optimal condition for producing nanochitosan with good antimicrobial activity and suitable characteristics. Keywords: Nanochitosan, shrimp shells, sodium hypochlorite, bleaching, antimicrobial.]]>
