title: Optimization of proteins and minerals removal from shrimp shells to produce highly acetylated chitin.
abstract: Chitin and derivatives used for biomedical or pharmaceutical applications require a high level of purity and quality that are difficult to achieve. In this study, we propose to optimize the extraction of chitin in order to obtain pure product keeping a structure as close as possible to the native form. Thus, demineralization step was firstly optimized using response surface methodology. In the optimized conditions predicted by the model, the obtained chitin has an acetylation degree (DA) and a demineralization degree (DM) equal to 99% and 100%, respectively. Then, different microbial and fish crude alkaline proteases were tested for their efficiency in deproteinization. Crude alkaline proteases giving the highest deproteinization degrees (DP), Bacillus mojavensis A21 and Scorpaena scrofa, were selected for chitin extraction. The obtained DP was 88±2% and 83±1%, respectively. At the end, effect of the use of mixed enzymatic treatment with the two selected crude enzymes and the order of demineralization/deproteinization steps were tested. The results demonstrated that two separated steps in enzymatic treatments realized on demineralized sample give the best DP (96%) preserving the DA (99%).
authors: Laboratory of Enzyme Engineering and Microbiology, ENIS, P.O. Box 1173-3038 Sfax, Tunisia. Electronic address: islem.younes@gmail.com.
authors: Islem
authors: I
authors: Younes
authors: Laboratory of Enzyme Engineering and Microbiology, ENIS, P.O. Box 1173-3038 Sfax, Tunisia.
authors: Sawssen
authors: S
authors: Hajji
authors: Biomaterials Applications, 6, rue Lesdiguières, 38000 Grenoble, France.
authors: Marguerite
authors: M
authors: Rinaudo
authors: Laboratory of Industrial Chemistry, ENIS, BP W 3038 Sfax, Tunisia.
authors: Moncef
authors: M
authors: Chaabouni
authors: Laboratory of Enzyme Engineering and Microbiology, ENIS, P.O. Box 1173-3038 Sfax, Tunisia.
authors: Kemel
authors: K
authors: Jellouli
authors: Laboratory of Enzyme Engineering and Microbiology, ENIS, P.O. Box 1173-3038 Sfax, Tunisia.
authors: Moncef
authors: M
authors: Nasri
mesh_terms: D000107:Acetylation; D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D001407:Bacillus / Q000201:enzymology; D001673:Biodegradation, Environmental; D002686:Chitin / Q000737:chemistry*; D003445:Crustacea / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*
chemical_list: D008903:Minerals; D011506:Proteins; D002686:Chitin; D010447:Peptide Hydrolases
keywords: Chemical demineralization; Chitin; Enzymatic deproteinization