Keywords: Chitosan; squid pen; seafood wastes; antimicrobial activity; demineralization

Abstract

Chitosan is a versatile polysaccharide with applications across various industries due to its characteristics and antimicrobial properties. The physicochemical features and biological properties of chitosan are closely associated with its degree of deacetylation (DDA), which can be influenced by the selection of raw materials and the extraction process. This study aimed to evaluate the characteristics and antimicrobial potential of chitosan obtained from squid pen cartilage originating from different waste sources, namely restaurant waste (S) and market waste (SS), using chemical extraction methods, with and without demineralization step. Analyses using Ultraviolet-visible and Fourier-transform infrared spectroscopy spectrophotometers showed the presence of chitosan in all samples and identified the functional groups within the chitosan molecules. Chitosan yields ranged from 55-82.4%, while the DDA values were between 73.67-76.64%. All chitosan samples demonstrated antimicrobial activity against the tested Gram-positive and Gram-negative bacteria, with inhibition zones ranging from 9.5 ± 0.7 mm to 13.5 ± 2.1 mm using the agar well diffusion method. The MIC values for all chitosan samples varied from 25 to 100 μg/mL, while MBC values were in the range of 50 to 100 μg/mL, and MFC values against A. niger ranged from 25 to 100 μg/mL. The results indicate that chitosan derived from squid pen waste sources exhibits potential as a natural antimicrobial agent, and its DDA remains unaffected by the omission of the demineralization step.