EXPLORING ALKALINE PROTEASE ACTIVITY OF BACILLUS STRAIN ISOLATED FROM SIDON DUMPSITE LEBANON

Proteases are crucial hydrolytic enzymes present in all organisms, performing essential physiological and industrial tasks. This study was conducted to screen and isolate protease-producing bacteria from soil and water samples collected from Sidon dumpsite in Lebanon. Bacterial samples were cultured onto skim milk agar medium to identify the alkaline protease-producing ones. In this study, we report on the partial purification and characterization of one of the isolated alkaline protease-producing bacteria. The bacterium was identified as Bacillus subtilis Z3 based on 16S rRNA sequencing. The molecular weight of the partially purified protease was approximately 55 kDa, estimated by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Enzyme activity was determined under varying conditions of pH, incubation time, temperature, and carbon and nitrogen sources. The maximum protease activity was observed at 37 oC and pH 9.0, which was strongly activated by two metal ions, mainly Ca+2 and Mg+2. Phenylmethylsulphonyl fluoride fully inhibited the enzyme activity, indicating that this protease is a member of the serine protease family. Furthermore, the enzyme exhibited significant stability upon being exposed to different surfactants and solvents. Inclusion of this protease in detergents enhanced their ability to remove blood stains as well as to degrade feathers. Therefore, this isolated bacterial protease could be a valuable option for the detergent industry.