Extraction, Partial Purification, Characteristics, and Antimicrobial Activity of Plant Protease From Moringa Oleifera Leaves

Proteases are hydrolyzing enzymes and are considered to be one of the most important groups of enzymes for industry and are used in leather, pharmaceutical, and food industry along with detergents, and bioremediation processes. The main objectives of this study were (i) to extract, partially purify, and characterize the protease enzyme from Moringa (Moringa oleifera) leaves; and (ii) to investigate the effect of such an enzyme against some pathogenic bacteria.

This enzyme was extracted in a 0.1 M phosphate buffer pH 7. It was left for 24 hours in a refrigerator and was then filtered using filter paper Whatman no. 41. The aqueous filtrate was used to estimate the proteolytic activity.

Purification by ammonium sulfate gave the best results at 50%-70% concentration which had the highest specific activity, highest purification fold with the percentage yield of 45.3%. Gel filtration by Sephadex G-100 gave the best specific activity and the best purification fold with the yield from fraction of 34%-43%. The protease enzyme has optimum pH 7 and temperature 50 oC. The enzyme was thermally stable at 40-70 oC for 20-30 minutes. Some metal ions were activator on the enzyme-like Mn2+ (highest), Ba2+, Ca2+, and Na+. The efficacy of protease enzyme was improved when integration with antibiotic against certain bacterial including Bacillus cereus (S3), Staphylococcus aureus, Salmonella typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes. Also, E. coli O157:H7, L. monocytogenes, and Yersinia enterocolitica did not show any growth at pH 10.

To conclude, it can be stated that protease enzyme can be considered as a promising agent, cheap, and safe source which is suitable for using in various industries.