Production and purification of novel thermostable alkaline protease from Anoxybacillus sp. KP1

In this study, an extracellular novel alkaline protease (EC 3.4.21-24, 99) from a thermophilic and aerobic strain of Anoxybacillus sp. KP1 has been studied. Maximum protease activity was obtained at 50 degC at pH 9.0 after 24 hours of incubation. Among the carbon and nitrogen sources used; the optimum protease production was with soluble starch, maltose, urea and casamino acid. The enzyme was purified by ammonium sulphate precipitation and Sephadex G-75 gel chromatography. Molecular weight of purified enzyme was determined as 106 kDa by SDS-PAGE. Purified protease was stable at 50-60 °C and at pH 9.0 for 1 h. The enzyme activity was increased in the presence of Ca2+, Cu2+, Tween 80 and Triton X-100, however the enzyme activity was inhibited in the presence of Hg2+, ethylene diamine tetra acetic acid (EDTA) and H2O2. Proteolytic activity was completely inhibited by phenyl methyl sulfonyl fluoride (PMSF). The enzyme seems to be a serine alkaline protease. In the presence of detergents, the protease was clearly stable and residual activity was between 73-82%.