Preliminary screening and characterization of novel proteolytic enzymes produced by extremophilic bacteria isolated from Tunisian and Algerian biotopes.

The current paper reports on the production and characterization of extracellular thermostable proteases produced from thermophilic bacteria namely Aeribacillus pallidus VP3, Anoxybacillus kamchatkensis M1V, Virgibacillus natechei FarDT, and Melghiribacillus thermohalophilus Nari2AT strains isolated from different extremophlic biotopes in Tunisia and Algeria. The key challenge of the use of the different proteases in industrial applications is their efficiency under unconventional conditions. An optimization via one-factor-at-a-time (OFAT) methodology has been used to obtain 3,000 U.mL-1; 4,600 U.mL-1; 15,800 U.mL-1; and 16,000 U.mL-1 of proteases activity from VP3, M1V, FarDT, and Nari2AT strains, respectively. Particularly, VP3 and FarDT proteases showed a high tolerance to several organic solvents. In addition, the protease produced from FarDT strain might be useful as potential candidate for application in detergency. The deproteinization of shrimp wastes by M1V and Nari2AT proteases was successful with a high rate of deproteinization of about 48% and 82%. The obtained proteolytic hydrolysate obtained by M1V strain showed high biological activities with half maximal inhibitory concentration (IC50) of 71.52 µg.mL-1, 107.67 µg.mL-1, and 133.24 µg.mL-1, respectively for the angiotensin, tyrosinase, and amylase inhibitory activities. [ABSTRACT FROM AUTHOR]