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

Document Type : Research Paper


1 Department of Biology, Faculty of Science, Razi University, Kermanshah, Iran

2 Department of biology, Faculty of Sciences, Razi University, Kermanshah, Iran


Background: Proteases play an important role in food, leather, detergent, and medical technologies.
Objectives: In the current study, an alkaliphilic solvent-stable thermotolerant metalloprotease was isolated from Bacillus sp. DEM05.
Material and Methods: For culture optimization, carbon, and nitrogen sources as well as incubation temperature, pH, and time were examined.
Results: 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.
Conclusions: 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.


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