title: Surfactant- and oxidant-stable alkaline proteases from Bacillus invictae: Characterization and potential applications in chitin extraction and as a detergent additive.
abstract: A newly alkaline proteases producing strain was isolated from sea water. The strain was identified as Bacillus invictae on the basis of biochemical characteristics and 16S rRNA sequence analysis. The crude protease activity showed an optimal activity at approximately 60°C and in wide pH interval ranging from 9.0 to 11.0. At least six clear caseinolytic protease bands were observed in a zymogram. Phenylmethylsulfonyl fluoride (PMSF), a serine-protease inhibitor, was found to inhibit completely the protease activity. The crude alkaline proteases showed high stability toward solid and liquid detergents. Furthermore, wash performance analysis revealed that the crude enzyme could effectively remove blood stain when added to commercial detergent. In addition, the crude proteases were found to be effective in the deproteinization of shrimp shell waste. The percent of protein removal after 3h of hydrolysis at 50°C with an E/S ratio of 10U/mg of protein or after fermentation by the strain were about 76% and 82%, respectively. Thus, the results of the present study showed that the crude proteases of B. invectae could be effectively used in several industrial applications, as an eco-friendly agent.
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie. Electronic address: amal.hammami1@gmail.com.
authors.forename: Amal
authors.initials: A
authors.lastname: Hammami
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie.
authors.forename: Marwa
authors.initials: M
authors.lastname: Hamdi
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie.
authors.forename: Ola
authors.initials: O
authors.lastname: Abdelhedi
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie.
authors.forename: Mourad
authors.initials: M
authors.lastname: Jridi
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie.
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173-3038 Sfax, Tunisie.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bayoudh
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002686:Chitin / Q000302:isolation & purification*; D003902:Detergents / Q000494:pharmacology*; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology*; D013696:Temperature; D014866:Waste Products
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D004791:Enzyme Inhibitors; D008670:Metals; D016877:Oxidants; D014866:Waste Products; D002686:Chitin; D010450:Endopeptidases; C087822:alkaline protease; D002118:Calcium
keywords: Bacillus invictae; Chitin; Detergent-alkaline proteases