Purification and Characterization of an Extracellular Alkaline Solvent-stable Metalloprotease Secreted from Newly Isolated Bacillus sp. DEM05: Optimization of Protease Production

Proteases play an important role in food, leather, detergent, and medical technologies. In the current study, an alkaliphilic solvent-stable thermotolerant metalloprotease was isolated from Bacillus sp. DEM05. For culture optimization, carbon, and nitrogen sources as well as incubation temperature, pH, and time were examined. Herein the highest outcome for bacterial growth and protease production was obtained after 72 h incubation (pH 7) at 37 °C. DEM05 protease was successfully purified and the specific activity of the protease was 1075 U.mg-1. The purity of the enzyme was verified by SDS-PAGE electrophoresis as a single band of 30 kDa. The optimal activity of the enzyme was at pH 10 and 50 °C. H2O2, SDS, Triton X-100, Zn2+, Co2+, and Cu2+ could increase the protease activity. EDTA inhibited the protease activity, revealed that it can be classified as a metalloprotease. The enzyme was compatible with the water-miscible and water-immiscible organic solvents and proteolyzed several substrates, implying the wide substrate specificity. The results brought convincing evidence that DEM05 protease could be recruited as a novel prevailing protease that can be earmarked on industrial and medical technologies.