Protease activity of extracellular enzyme produced by B. subtilis isolated from soil

Abstract

Background: Proteases produced by enzymatic method are more environments friendly than chemical process, and they have tremendous potential in the leather industry and in other several industries. In this study extracellular protease producing non pathogenic Bacillus subtilis was isolated from soil sample and relationship between sporulation and extracellular protease synthesis in large scale cultivation was studied. The enzyme was further characterized, purified, and tested for potential application. Result: The molecular weight of the protease was found to be ~30 KDa. Enzyme activity was checked on the presence of different metal ions and effectors. The enzyme was slightly modulated by MG++ ion, and significantly by Hg++ ion, while Zn++ ion slightly decrease the proteolytic activity. Sulfahydryl reagents, DTT slightly and β-ME significantly inhibit the enzyme. EDTA showed no effect on the enzyme suggesting that the enzyme might not be metalloprotease. PMSF, a known serine protease inhibitor was seen to totally inhibit the enzyme which indicates that the enzyme is a serine protease. The optimum enzyme activity was observed after 22 hours of incubation of B. subtilis at 37o C. Conclusions: Crude enzyme contains 285 units of enzyme which have direct dehairing activity. The enzyme was also seen to be able to remove blood and curry stain from clothes; making it a very promising candidate to be used in a leather and detergent industry. Apart from protease the bacterium was also seen to have lipase and collagenase activity. So, the bacteria are potentially good candidate for industrial application