Isolation and optimization of the method for industrial production of chitin and chitosan from Omani shrimp shell

Chitosan is an organic compound widely used in biomedical and agricultural fields due to its medicinal values. Chitosan is the largest biopolymer after cellulose and it is used as a food supplement as well as a primary health care product. The focus of the present study is to optimize the method for isolation and characterization of chitosan from Omani shrimp shell. The chitosan was isolated chemically from shrimp waste through the chemical processes of demineralization, deproteinization, discoloration and deacetylation. Chitosan isolation was done using hydrochloric acid (HCl), sodium hydroxide (NaOH) and hydrogen peroxide (H₂O₂) at various concentrations and temperatures during the demineralization, the deproteinization, and the deacetylation processes. A total of twenty-seven samples were run in triplicate and used to isolate chitin from shrimp shell and then different methods of deacetylation were done to extract chitosan. The research was conducted by changing three variables such as the concentration of acid and base and temperature. The coarse powder shrimp waste samples were demineralized by varying the concentrations ranging from 3 to 9% of HCl and at the temperature range between 25 and 55 °C. The demineralized samples were treated with different concentrations of NaOH ranging from 20 to 60% and at the temperature range from 85 to 110 °C to deproteinize the samples. The optimal method for chitin isolation was selected by using FT-NIR spectroscopy. The optimal experimental conditions according to the present study were 3% HCl at 25 °C for an hour demineralization and 50% NaOH at 110 °C for 3 h deproteinization with a yield of 53.313%. Finally, the isolated chitin was decolorized by treatment with 30% H₂O₂ for 3 h then deacetylatised with 50% NaOH for 15 min. The weight loss was 0.29 gm/5 gm. In conclusion, shrimp waste could be a natural alternative source for the production of chitin. Furthermore, it could be used in medical, pharmaceutical, and biotechnology sectors.