Characterization of a novel protease from Aeribacillus pallidus strain VP3 with potential biotechnological interest

The present study investigates the purification and physico-chemical characterization of an extracellular protease from the Aeribacillus pallidus strain VP3 previously isolated from a geothermal oil-field (Sfax, Tunisia). The maximum protease activity recorded after 22 h of incubation at 45 degrees C was 3000 U/ml. Pure enzyme, designated as SPVP, was obtained after ammonium sulfate fractionation (40-60%)-dialysis followed by heat-treatment (70 degrees C for 30 min) and UNO Q-6 FPLC anion-exchange chromatography. The purified enzyme is a monomer of molecular mass about 29 kDa. The sequence of the 25 NH2-terminal residues of SPVP showed a high homology with those of Bacillus proteases. The almost complete inhibition by PMSF and DIFP confirmed that SPVP is a member of serine protease family. Its optima of pH and temperature were pH 10 and 60 degrees C, respectively. Its half-life times at 70 and 80 degrees C were 8 and 4h, respectively. Its catalytic efficiency was higher than those of SAPCG, Alcalase Ultra 2.5 L, and Thermolysin type X. SPVP exhibited excellent stability to detergents and wash performance analysis revealed that it could remove blood-stains effectively and high resistance against organic solvents. These properties make SPVP a potential candidate for applications in detergent formulations and non-aqueous peptide biocatalysis. (C) 2016 Elsevier B.V. All rights reserved.