Synthesis, Characterization, and Antibacterial Activity of Chitosan Derived from Charru Mussel (Mytella charruana) Shells in Baroy, Lanao del Norte, the Philippines

Charru mussel, an invasive species found along the coastal areas of Baroy, Lanao del Norte, the Philippines, is commonly processed into the local delicacy known as “amahong,” with the shells often discarded as waste from this practice. This study aims to extract chitosan through demineralization of charru mussel shells using 1.25 N HCl, deproteinization using 3% NaOH yielding chitin, and deacetylation of chitin using 45% NaOH. The result shows a chitin yield of 21.27 ± 0.98% and a chitosan yield of 11.07% ± 0.66%. ATR-FTIR analysis confirmed the characteristic bands and functional groups associated with chitosan. SEM imaging revealed an amorphous and uneven particle shape, and TGA results exhibited thermal degradation at 550 °C, at which point chitosan breaks down. The synthesized chitosan displayed antibacterial activity at all concentrations (100, 200, and 300 μg/mL) against S. aureus while ineffective against E. coli. This study underscores the untapped potential of charru mussel shells as a source of chitosan, offering valuable insight for waste management.