Extraction of chitin from edible crab shells of Callinectes sapidus and comparison with market purchased chitin

Abstract

Chitin and its derived products have immense economic value due to their vital role in various biological activities as well as biomedical and industrial application. Insects, microorganism and crustaceans are the main supply of chitin but the crustaceans shell like shrimp, krill, lobsters and crabs are the main commercial sources. Chitin content of an individual varies depending on the structures possessing the polymer and the species. In this study edible crabs’ shells (Callinectes sapidus) were demineralized and deproteinized resulting in 13.8% (dry weight) chitin recovery from chitin wastes. FTIR and XRD analyses of the experimental crude as well as purified chitins revealed that both were much comparable to the commercially purchased controls. The acid pretreatment ceded 54g of colloidal chitin that resulted in 1080% of the crude chitin. The colloidal chitin was exploited for isolation of eighty five chitinolytic bacterial isolates from different sources. Zone of clearance was displayed by the thirty five isolates (41.17%) succeeding their growth at pH 7 on colloidal chitin agar medium. Maximum chitinolytic activity i.e. 301.55 U/ml was exhibited by isolate JF70 when cultivated in extracted chitin containing both carbon and nitrogen. The study showed wastes of blue crabs can be utilized for extraction of chitin and isolation of chitinolytic bacteria that can be used to degrade chitin waste, resolve environmental pollution as well as industrial purpose.