Thermotolerant alkaline protease enzyme from Bacillus licheniformis A10: purification, characterization, effects of surfactants and organic solvents

Abstract

In this study, the extracellular thermostable alkaline protease out of A10 strain was purified 1.38-fold with 9.44% efficiency through the ammonium sulfate precipitation-dialysis and DE52 anion exchange chromatography methods. The molecular weight of the enzyme in question along with sodium dodecyl sulfate-polyacrylamide gel electrophoresis was determined to be approximately 40.55 kDa, whereas the optimum pH and temperature ratings were identified as 9.0 and 70 °C, respectively. It was seen that the enzyme had remained stable between pH 7.5–10.5 range, protecting more than 90% of its activity in the wake of 1 h incubation at 60–70 °C. It was also observed that the enzyme enhanced its activity in the presence of Mg2+, Mn2+, K+, while Fe2+, Ni2+, Zn2+, Ag+ and Co2+ decreased the activity. Ca2+, however, did not cause any change in the activity. The enzyme was seen to have been totally inhibited by phenylmethylsulfonyl fluoride, therefore, proved to be a serine alkaline protease.