Zebra blenny (Salaria basilisca) viscera as a source of solvent-stable proteases: characteristics, potential application in the deproteinization of shrimp wastes and evaluation in liquid laundry commercial detergents

The present study describes the characterization of crude protease extract from zebra blenny (Salaria basilisca) and its evaluation in liquid detergent and shrimp waste deproteinization. At least five caseinolytic proteases clear bands were observed in zymogram. The crude alkaline protease showed optimum activity at pH 8.0 and 60 degrees C, and it was highly stable over a wide range of pH from 6.0 to 11.0. Proteolytic enzymes showed extreme stability towards non-ionic surfactants (5 % Tween 80 and 5 % Triton X-100) and oxidizing agents (1 % sodium perborate), and relative stability towards anionic surfactant (1 % Sodium dodecyl sulfate (SDS)). They also showed high stability and compatibility with various laundry liquid detergents from Tunisian market. Furthermore, the crude enzyme was stable towards several organic solvents and retained more than 50 % of its original activity after 30 days of incubation at 30 degrees C in the presence of 50 % (v/v) dimethylsulfoxide (DMSO). Further, proteases from zebra blenny viscera were found to be effective in the deproteinization of shrimp wastes. The protein removal after 3 h at 40 degrees C with an enzyme/substrate ratio (E/S) of 5 U/mg protein was about 77 %.