Chitin extraction from shrimp shell waste using Bacillus bacteria

• Published in: International journal of biological macromolecules Vol. 51; no. 5; pp. 1196 - 1201
• Main Authors: Ghorbel-Bellaaj, Olfa, Younes, Islem, Maâlej, Hana, Hajji, Sawssen, Nasri, Moncef
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2012
• Subjects: 2,2-diphenyl-1-picrylhydrazyl; Animal Shells - chemistry; Animals; Antioxidant activity; Bacillus; Bacillus - growth & development; Bacillus - metabolism; Bacillus amyloliquefaciens; Bacillus cereus; Bacillus licheniformis; Bacillus pumilus; Bacillus subtilis; Biphenyl Compounds - chemistry; Chitin; Chitin - biosynthesis; Chitin - chemistry; Chitin - isolation & purification; Culture Media - chemistry; Decapoda (Crustacea) - chemistry; Demineralization; Deproteinization; Fermentation; free radical scavengers; Free Radical Scavengers - chemistry; Free Radical Scavengers - isolation & purification; Free Radical Scavengers - metabolism; glucose; Glucose - chemistry; hydrolysates; Industrial Waste; inhibitory concentration 50; Iron Chelating Agents - isolation & purification; Iron Chelating Agents - metabolism; Iron Chelating Agents - pharmacology; Oxidation-Reduction; Peptide Hydrolases - biosynthesis; Picrates - chemistry; shrimp; Shrimp waste; wastes; Chitin; Demineralization; Fermentation; Deproteinization; Antioxidant activity; Shrimp waste
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2012.08.034

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 IC50 value of 0.3mg/ml. Highest reducing power (DO 700nm=1.55 at 1.5mg/ml) and metal chelating activity (98% at 5mg/ml) were obtained with B. pumilus A1 and B. licheniformis RP1 hydrolysates, respectively.