Optimizing the Extraction of Pure chitin and chitosan from chitinous shells of Litopenaeus vannamei and Portunus pelagicus Species

Optimization of standard methods of marine compounds leads to acquire chitin and chitosan with highest purity from chitinous wastes and shells with extensive use in pharmaceutical and industrial applications. In this research, Litopenaeus vannamei and Portunus pelagicus shells were used as wastes to extract these valuable compounds. For this reason, two extraction methods were applied for chitin. The first method was deproteinization with 10%NaOH, demineralization with 15% HCL, degreasing with 15% NaOH and decoloration with aceton. While, the second method carried out applying decoloration first with 3% sodium hypochlorite, demineralization by 1M HCL and then deproteinization with 1M NaOH. Chitosan was extracted by deacetylation of acquired chitin. Results indicated that the percentage of extracted chitin from shrimp and crab shells in first method were 75.3% and 58% and in second method were 30.26% and 37.8%, respectively. Therefore, the first extraction method was selected for chitosan isolation. The amount of chitin found in claw and legs of the crab was (58% ±0.07) and segments of shrimp body was (81% ±0.12) which was higher than the amount of chitin in carapace shells (P <0.05). The percentage of extracted chitosan from shrimp and crab shells were 29.3% and 31.02%, respectively. The degree of deacetylation of chitosan obtained from chitinous shells of two species in this research were 45% (Shrimp shells) and 52.63% (crab shells), respectively. Use of waste chitinous shells of shrimp and crab species will be useful for both remediation of wastes from environment and increment the manufacture of economically important marine products.