Purification and characterization of an extracellular thermotolerant alkaliphilic serine protease secreted from newly isolated Bacillus sp. DEM07 from a hot spring in Dehloran, Iran

Publication date: Available online 22 February 2019Source: Biocatalysis and Agricultural BiotechnologyAuthor(s): Lale Nazari, Maryam MehrabiAbstractThe current study examines a thermotolerant alkaliphilic serine protease from newly isolated Bacillus sp. DEM07, which was purified with a 20% total protein yield and 14.28 fold purification. The molecular weight of the enzyme was estimated to be 27.5 kDa. The Km and Vmax values of the purified enzyme were found to be 0.06 mg/ml and 1.25 μmol/min, respectively. The enzyme maintained activity and stability over the 30–55 °C temperature range exhibiting its optimum activity at 50 °C. Furthermore, high activity and stability were found over a wide range of pH from 4 to 11 with a supreme at pH 10. CTAB, TritonX-100, SDS, and H2O2 significantly enhanced the protease activity by 300, 266, 136, and 158%, respectively. The protease was inhibited by PMSF, suggesting that it can be a serine protease. Acetone and DMSO appeared as the most potent, increasing protease activity up to 216 and 105%, respectively. The enzyme retained more than 70% of its initial activity in the other organic solvents. DEM07 protease was capable of proteolyzing various substrates, suggesting broad substrate specificity. Considering these properties, the enzyme could be applied as a novel potent protease in industrial and biotechnological processes.
Source: Biocatalysis and Agricultural Biotechnology - Category: Biotechnology Source Type: research