Production, Optimization and Partial Characterization of Alkaline Protease from Bacillus subtilis spp. subtilis NRRL B-3384 and B-3387

Bacillus subtilis has been a reliable platform for the expression of extracellular proteases for several decades. Although a majority of Bacillus subtilis subspecies express proteases, the amount of secreted enzyme varies depending on the strain and environmental conditions used. Here, two Bacillus subtilis spp. subtilis strains, NRRL B-3384 and NRRL B-3387, from the ARS Culture collection (NRRL), were compared for secreted protease activity. The highest activity was found in strain NRRL B-3384, and proteolysis occurred at temperatures as high as 80°C and across a broad range of pH, with maximum activity at pH 9.0 and 60°C indicating the presence of a thermostable alkaline protease. To our knowledge, this is the first study to evaluate protease production in Bacillus subtilis spp. subtilis strains NRRL B-3384 and B3387 and suggests that NRRL B-3384 may have utility in the production of enzymes for industrial use.