Fungal-Derived Chitosan from In Vitro Mushroom Cultures as an Antimicrobial Matrix for Silver Nanoparticles in Advanced Bioactive Materials

This study investigates chitosan extracted from <i>in vitro</i> cultures of <i>Hericium erinaceus</i> and <i>Pleurotus ostreatus</i> mushrooms as a novel antimicrobial matrix. The physicochemical properties including specific surface area, pore volume, and molecular structure were characterized by BET, SEM, and FTIR-ATR analyses. Chitosan from <i>P. ostreatus</i> exhibited a higher specific surface area (0.39 m²/g) compared to <i>H. erinaceus</i> (0.73 m²/g) and commercial chitosan (1.16 m²/g), correlating with enhanced antimicrobial activity against Gram-negative and Gram-positive bacterial strains. Antibacterial efficacy was quantitatively evaluated by inhibition zone diameters, with <i>P. ostreatus</i> chitosan combined with silver nanoparticles achieving an average zone of 18.2 ± 0.5 mm against <i>Escherichia coli</i>, a 25% increase compared to chitosan alone. Thermal analysis showed improved stability upon silver modification, with endothermic peak shifts from 85 °C to 118 °C. These results demonstrate that fungal-derived chitosan, particularly from <i>P. ostreatus</i>, provides a bioactive matrix with significant antibacterial properties, supporting its potential for biomedical applications. The incorporation of quantitative metrics enhances the robustness and reproducibility of the findings.