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.
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Marwa
M
Hamdi
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Amal
A
Hammami
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Sawssen
S
Hajji
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia. Electronic address: jridimourad@gmail.com.
Mourad
M
Jridi
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Moncef
M
Nasri
Laboratory of Enzyme Engineering and Microbiology, University of Sfax, National Engineering School of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Rim
R
Nasri
D000818:Animals; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003386:Brachyura / Q000737:chemistry* / Q000201:enzymology; D002686:Chitin / Q000302:isolation & purification*; D004063:Digestion; D010450:Endopeptidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D033561:Penaeidae / Q000737:chemistry*; D011480:Protease Inhibitors / Q000494:pharmacology; D013696:Temperature; D014781:Viscera / Q000201:enzymology*
D001426:Bacterial Proteins; D008670:Metals; D011480:Protease Inhibitors; D002686:Chitin; D010450:Endopeptidases; C087822:alkaline protease
Blue crab and shrimp shells chitins; Digestive alkaline proteases; Enzymatic deproteinization