Chitin extraction from blue crab (Portunus segnis) and shrimp (Penaeus kerathurus) shells using digestive alkaline proteases from P. segnis viscera.
Since chitin is closely associated with proteins, deproteinization is a crucial step in the process of extracting chitin. Thus, this research aimed to extract chitin from Portunus segnis and Penaeus kerathurus shells by means of crude digestive alkaline proteases from the viscera of P. segnis, regarding deproteinization step, as an alternative to chemical treatment. Casein zymography revealed that five caseinolytic proteases bands exist, suggesting the presence of at least five different major proteases. The optimum pH and temperature for protease activity were pH 8.0 and 60°C, respectively, using casein as a substrate. The crude enzymes extract was highly stable at low temperatures and over a wide range of pH from 6.0 to 12.0. The crude alkaline protease extract was found to be effective in the deproteinization of blue crab and shrimp shells, to produce chitin. The best efficiency in deproteinization (84.69±0.65% for blue crab shells and 91.06±1.40% for shrimp shells) was achieved with an E/S ratio of 5U/mg of proteins after 3h incubation at 50°C. These results suggest that enzymatic deproteinization of crab and shrimp wastes by fish endogenous alkaline proteases could be a potential alternative in the chitin production process.
['Hamdi|Marwa|M|', 'Hammami|Amal|A|', 'Hajji|Sawssen|S|', 'Jridi|Mourad|M|', 'Nasri|Moncef|M|', 'Nasri|Rim|R|']
D000818:Animals D001426:Bacterial Proteins D003386:Brachyura D002686:Chitin D004063:Digestion D010450:Endopeptidases D006863:Hydrogen-Ion Concentration D008670:Metals D033561:Penaeidae D011480:Protease Inhibitors D013696:Temperature D014781:Viscera
Digestive alkaline proteases Enzymatic deproteinization Blue crab and shrimp shells chitins