Synthesis of Water-Soluble Chitosan from Crab Shells (Scylla Serrata) Waste

Water soluble chitosan (WSC) has been successfully synthesized from crab shells waste through several processes i.e. demineralization, deproteination, deacetylation, and depolimerization. Chitin was obtained by demineralization and deproteination of crab shells. While chitosan was obtained by deacetylation of chitin. Deacetylation of chitin was carried out at varied temperature i.e. 50, 60, 70, 80, 90, and 100 degrees C. The optimum yield of WSC was obtained at temperature of 90 degrees C. The IR spectra of chitin, chitosan, WSC were compared to those from literature. The highest deacetylation degrees (DD) of chitosan was 84.34% that obtained by deacetylation at 90 degrees C. While WSC highest DD value was 75.2% that obtained from chitosan that treated at 100 degrees C. The solubility test of WSC proved that chitosan was successfully converted into WSC. The optimum WSC solubility in water at room temperature was 1.842 g/L while at 40 C was 1.846 g/L that obtained from deacetylation of chitosan at 90 degrees C. While chitosan that treated at 100 degrees C has solubility in HC1 0.1 M of 1.908 g/L at at room temperature and 1.952 g/L at 40 degrees C.