Purification and biochemical characterization of two detergent-stable serine alkaline proteases from Streptomyces sp. strain AH4

• Published in: World journal of microbiology & biotechnology Vol. 31; no. 7; pp. 1079 - 1092
• Main Authors: Boulkour Touioui, Souraya, Zaraî Jaouadi, Nadia, Boudjella, Hadjira, Ferradji, Fatma Zohra, Belhoul, Mouna, Rekik, Hatem, Badis, Abdelmalek, Bejar, Samir, Jaouadi, Bassem
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2015; Springer Nature B.V
• Subjects: Amino acids; Analysis; Antibiotics; Applied Microbiology; Bacteria; Bacterial Proteins - drug effects; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biochemistry; Biomedical and Life Sciences; Biotechnology; Detergents; Detergents - pharmacology; Environmental Engineering/Biotechnology; Enzyme Stability; Enzymes; Hydrogen-Ion Concentration; Laboratories; Life Sciences; Microbiology; Microorganisms; Optimization; Original Paper; Phenylmethylsulfonyl Fluoride - pharmacology; Protease; Proteases; Sequence Homology, Amino Acid; Serine Proteases - drug effects; Serine Proteases - genetics; Serine Proteases - isolation & purification; Serine Proteases - metabolism; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Stability; Strain; Streptomyces; Streptomyces - enzymology; Streptomyces - growth & development; Studies; Substrate Specificity; Temperature; Yeast; MALDI-TOF/MS; Purification; Laundry detergent; Proteases
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-015-1858-6

Streptomyces sp. strain AH4 exhibited a high ability to produce two extracellular proteases when cultured on a yeast malt-extract (ISP2)-casein-based medium. Pure proteins were obtained after heat treatment (30 min at 70 °C) and ammonium sulphate fractionation (30–60 %), followed by size exclusion HPLC column. Matrix assisted laser desorption ionization-time of flight mass spectrometry analysis revealed that the purified enzymes (named SAPS-P1 and SAPS-P2) were monomers with molecular masses of 36,417.13 and 21,099.10 Da, respectively. Their identified N-terminal amino acid displayed high homologies with those of Streptomyces proteases. While SAPS-P1 was optimally active at pH 12.0 and 70 °C, SAPS-P2 showed optimum activity at pH 10.0 and 60 °C. Both enzymes were completely stable within a wide range of temperature (45–75 °C) and pH (8.0–11.5). They were noted to be completely inhibited by phenylmethanesulfonyl fluoride and diisopropyl fluorophosphates, which confirmed their belonging to the serine proteases family. Compared to SAPS-P2, SAPS-P1 showed high thermostability and excellent stability towards bleaching, denaturing, and oxidizing agents. Both enzymes displayed marked stability and compatibility with a wide range of commercial laundry detergents and significant catalytic efficiencies compared to Subtilisin Carlsberg and Protease SG-XIV. Overall, the results indicated that SAPS-P1 and SAPS-P2 can be considered as potential promising candidates for future application as bioadditives in detergent formulations.