study on activity and stability of proteases from bacillus sp. produced by submerged fermentation

Objective: investigations were carried out to isolate bacteria from saline-alkali soils and determined optimized alkaline protease activity and stability produced by a wild strain of bacillus sp. in submerged fermentation (smf). methods: optimum temperature for enzyme activity in the crude extract was 40 ◦c at a ph between 8.0 and 9.0. the studies on ph stability showed that the enzyme was stable in a range of ph 7.0–10.0 and the effect of the inhibitors showed it to be possibly an alkaline protease. stability studies revealed temperatures around 40–60 ◦c. results: the activity was reduced in the presence of co2+, fe2+ and zn2+ ions, while the presence of k+ resulted in a discreet increase in proteolytic activity. the enzyme presented good stability towards organic solvents. organic solvents such as 2-ethyl-1-hexanol and oleyl alcohol enhanced the activity of enzyme. the enzyme presented good stability towards oxidizing agent. the crude enzyme preparation was compatible with commercial detergents, retaining their 50–60% activities. conclusions: the results demonstrated the importance of submerged fermentation for the production of protease.