Structural differences between chitin and chitosan extracted from three different marine sources.
Three marine sources of chitin from Tunisia were investigated. Structural differences between α-chitin from shrimp (Penaeus kerathurus) waste, crab (Carcinus mediterraneus) shells, and β-chitin from cuttlefish (Sepia officinalis) bones were studied by the (13)C NMR, FTIR, and XRD diffractograms. The (13)C NMR analysis showed a splitting of the C3 and C5 carbon signals for α-chitin, while that of β-chitin was merged into a single resonance. The bands contour of deconvoluted and curve-fit FTIR spectra showed a more detailed structure of α-chitin in the region of O-H, N-H and CO stretching regions. IR and (13)C NMR were used to determine the chitin degree of acetylation (DA). XRD analysis indicated that α-chitins were more crystalline polymorph than β-chitin. Shrimp chitin was obtained with a good yield (20% on raw material dry weight) and no residual protein and salts. Chitosans, with a DA lower than 20% and relatively low molecular masses were prepared from the wet chitins in the same experimental conditions. They were perfectly soluble in acidic medium. Nevertheless, chitin and chitosan characteristics were depending upon the chitin source.
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia. Electronic address: hajjisawssen@yahoo.fr.
Sawssen
S
Hajji
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Islem
I
Younes
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Olfa
O
Ghorbel-Bellaaj
Laboratory of Solid State, Faculty of Science, University of Sfax, B.P. 802, 3018 Sfax, Tunisia.
Rachid
R
Hajji
Biomaterials Applications, 6, rue Lesdiguières, 38000 Grenoble, France.
Marguerite
M
Rinaudo
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Moncef
M
Nasri
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Kemel
K
Jellouli
D000107:Acetylation; D060105:Animal Shells / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D003386:Brachyura / Q000737:chemistry*; D002686:Chitin / Q000737:chemistry* / Q000302:isolation & purification*; D048271:Chitosan / Q000737:chemistry* / Q000302:isolation & purification*; D049832:Decapodiformes / Q000737:chemistry*; D008903:Minerals / Q000302:isolation & purification; D008970:Molecular Weight; D033561:Penaeidae / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000378:metabolism; D014783:Viscosity
D008903:Minerals; D002686:Chitin; D048271:Chitosan; D010447:Peptide Hydrolases
Carcinus mediterraneus; Chitin; Penaeus kerathurus; Sepia officinalis