Effect of NaOH-based deproteinisation on chemical and biological properties of Moina sp. chitosan

Chitosan is a biopolymer which is isolated from the crustacean exoskeleton of Moina sp. with particular antibacterial properties. Alkali-sodium hydroxide deproteinisation has a huge role in ensuring the chitosan quality by removing protein to enhance its dispersivity. Modification of sodium hydroxide (NaOH) concentration by 3N and 6N was performed in this study to observe the effect on chemical and biological characteristics of chitosan. The highest concentration treatment of 6N NaOH exhibited the best composition of protein, fat, and ash by 6.09%, 3.77% and 0.9%, respectively. The deacetylation degree of chitosan treated with 3N NaOH depicted the highest solubility of 73.25% compared to the solubility of 6N NaOH by 61.06%. The antibacterial activity of Moina sp. chitosan was considered as having a weak and fluctuated activity by different concentrations of NaOH. The 6N NaOH treatment chitosan showed the best antibacterial activity against the grampositive bacterial strain of Staphylococcus aureus with the widest inhibition zone diameter of 4.34±0.55 mm, while the 3N NaOH treatment chitosan showed the best antibacterial activity against the gram-negative bacterial strain of Escherichia coli with widest inhibition zone diameter of 4.47±0.78 mm.