Purification and characterization of a solvent and detergent-stable novel protease from Bacillus cereus

A protease-producing bacterium was isolated from slaughterhouse waste samples, Hyderabad, India. It was related to Bacillus cereus on the basis of 16S rRNA gene sequencing and biochemical properties. The protease was purified to homogeneity using ammonium sulfate precipitation, and ion exchange chromatography with a fold purification of 1.8 and a recovery of 49%. The enzyme had a relative molecular weight of 28kDa, pH and temperature optima for this protease were 10 and 60 degrees C. The activity was stable between a pH range of 7.0 and 12.0. The activity was inhibited by EDTA and enhanced (four-fold) by Cu(2+) ions indicating the presence of metalloprotease. The enzyme showed extreme stability and activity even in the presence of detergents and anionic surfactants. The enzyme also showed stability in the presence of organic solvents.