초록
<P><B>Abstract</B></P> <P>An extracellular alkaline stable protease BS1 from a new bacteria strain, <I>Bacillus safensis</I> S406, isolated from the Sfax solar saltern, was purified and characterized. The enzyme was purified to homogeneity by ammonium sulfate precipitation, Sephadex G-75 gel filtration, Mono-Q anion-exchange chromatography and ultrafiltration, with a 12.70-fold increase in specific activity and 20.29% recovery. The enzyme has a molecular weight of 29kDa and appeared as a single band on native-PAGE. The optimum pH and temperature values of its proteolytic activity were pH 11.0 and 60°C, respectively. BS1 was tested for the deproteinization of shrimp wastes to extract chitin. An enzyme-protein ratio of 10U/mg of proteins allows to eliminate 93% of protein linked to the chitin after 3h hydrolysis at 45°C. Being very active in alkaline conditions, the potential application of BS1 in laundry formulation was investigated. The enzyme showed high stability in the presence of non-ionic surfactants and some commercial liquid and solid detergents, suggesting its eventual use in detergent formulations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel protease from <I>Bacillus safensis S406</I> was purified (SB1) and characterized. </LI> <LI> BS1 with a molecular mass of 29kDa. </LI> <LI> Optimum pH and temperature values for activity were pH 10 and 60°C, respectively. </LI> <LI> BS1 is a potential candidate for peptide synthesis and detergent formulations. </LI> <LI> BS1 was found to be effective in the deproteinization of shrimp waste. </LI> </UL> </P>