Proteases; especially alkaline proteases, constitute the most used group of enzymes in
industry. The wide scope of their application requires varying properties; most commonly
stability throughout the conditional changes that would occur during the various industrial
processes. This study aimed to identify the potentially interesting bacterial strains obtained
from Moroccan extreme environment, and evaluate their proteolytic activity under the various
growing conditions. In this study, the impact of temperature and salinity on the alkaline
protease activity (pH 11) of 33 Bacillus strains deposited in the Moroccan Coordinated Culture
Collection, which originated from the various extreme environments from Morocco, was
studied. Bacterial identification to the species level was performed using 16S rRNA gene
sequencing and MultiLocus Sequence Typing (MLST), a technique that is much more precise
and can identify the bacteria to the strain level. Strain B950 showed a relatively stable protease
activity at the tested extreme conditions (i.e., 130.8 U/ ml at 60 °C and 10 % NaCl). On the
other hand, strain B961 displayed a better overall activity at either high temperature (140.8 U/
ml) or salinity (137 U/ ml); however, it was not as stable as when grown under both extreme
conditions. Regarding identity of the bacterial strains, they were all representatives of Bacillus
licheniformis; although B950 and B961 strains belonged to Sequence Types 3 and 5,
respectively.