Comparison of protease activities in different Bacillus licheniformis strains using wastewater sludge and synthetic soy medium as raw material.

The production of extracellular protease by different Bacillus licheniformis strains (ATCC 21415, ATCC 21417 and ATCC 21424) was tested in wastewater sludge as a raw material as well as in synthetic soy medium to compare the capacity of protease production by different strains and to compare the capacity of the medium to provide nutrients for enzyme synthesis. All of the strains showed similar activities in both media. The protease activity was very high in the fermentor in both of the media compared with the shake flask. Results from microbial selection indicated that ATCC 21424 had high potential for protease production using sludge as a growth medium. The observation from this study suggested that wastewater sludge could be used as a raw material (nutrient source) to produce protease for industrial applications.