Extraction, Synthesis, Characterization, and Molecular Docking Evaluation of a Chitosan‐Supported Schiff Base Derivative for Antifungal and Antimicrobial Applications

Chitosan was extracted from local shrimp shells with a yield of 35.0% and converted into a novel Schiff‐base derivative (Cht‐SS‐TIP) through condensation with 4‐[(5‐sulfanyl‐1,3,4‐thiadiazol‐2‐yl)imino]pentan‐2‐one. Structural confirmation via FTIR, elemental analysis, and SEM demonstrated successful functionalization, achieving a degree of deacetylation of 74.6% and a high substitution degree of 61.0%. Cht‐SS‐TIP exhibited a substantial improvement in biological performance relative to native chitosan. Antibacterial assays showed increased killing efficiencies ranging from 64% to 88%, with the strongest activity against Staphylococcus aureus and Bacillus subtilis . Antifungal evaluation revealed potent inhibition of 88% for Aspergillus fumigatus and 84% for A. niger , outperforming unmodified chitosan by more than 20%. Molecular docking against the Pseudomonas aeruginosa LasR quorum‐sensing regulator further supported these findings, yielding a favorable binding score of −8.4 kcal/mol and demonstrating stable interactions through hydrogen bonding with LEU110, THR75, ASP65, and π–π stacking with TRP88. The low re‐docking RMSD values (1.56 Å for the native ligand and 1.63 Å for Cht‐SS‐TIP) confirm protocol reliability. Overall, this study establishes Cht‐SS‐TIP as a high‐performance chitosan derivative that synergistically enhances antimicrobial efficacy through structural modification and quorum‐sensing inhibition, positioning it as a promising, sustainable candidate for disinfectant formulations and anti‐virulence strategies targeting resistant pathogens.