title: Chitin extraction from shrimp shell waste using Bacillus bacteria.
abstract: The ability of six protease-producing Bacillus species (Bacillus pumilus A1, Bacillus mojavencis A21, Bacillus licheniformis RP1, Bacillus cereus SV1, Bacillus amyloliquefaciens An6 and Bacillus subtilis A26) to ferment media containing only shrimp shell waste, for chitin extraction, was investigated. More than 80% deproteinization was attained by all the strains tested. However, demineralization rates not exceeding 67% were registered. Cultures conducted in media containing shrimp shell waste supplemented with 5% (w/v) glucose were found to remarkably promote demineralization efficiency, without affecting deproteinization rates. The antioxidant activities of hydrolysates, at different concentrations, produced during fermentation in medium supplemented with glucose, were determined using different tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method, reducing power assay and chelating activity. All hydrolysates showed varying degrees of antioxidant activity. Hydrolysate produced by B. pumilus A1 exhibited the highest DPPH radical scavenging activity, with an IC(50) value of 0.3 mg/ml. Highest reducing power (DO 700 nm=1.55 at 1.5 mg/ml) and metal chelating activity (98% at 5mg/ml) were obtained with B. pumilus A1 and B. licheniformis RP1 hydrolysates, respectively.
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173, 3038 Sfax, Tunisia. olfa_ghor@yahoo.fr
authors.forename: Olfa
authors.initials: O
authors.lastname: Ghorbel-Bellaaj
authors.forename: Islem
authors.initials: I
authors.lastname: Younes
authors.forename: Hana
authors.initials: H
authors.lastname: Maâlej
authors.forename: Sawssen
authors.initials: S
authors.lastname: Hajji
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
mesh_terms: D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D001407:Bacillus / Q000254:growth & development / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000737:chemistry; D002686:Chitin / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D003470:Culture Media / Q000737:chemistry; D033364:Decapoda / Q000737:chemistry*; D005285:Fermentation; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D005947:Glucose / Q000737:chemistry; D007220:Industrial Waste; D007502:Iron Chelating Agents / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D010084:Oxidation-Reduction; D010447:Peptide Hydrolases / Q000096:biosynthesis; D010851:Picrates / Q000737:chemistry
chemical_list: D001713:Biphenyl Compounds; D003470:Culture Media; D016166:Free Radical Scavengers; D007220:Industrial Waste; D007502:Iron Chelating Agents; D010851:Picrates; D002686:Chitin; C004931:1,1-diphenyl-2-picrylhydrazyl; D010447:Peptide Hydrolases; D005947:Glucose