Abstract
Microbial protease represents the most important industrial enzymes, which have an active role in biotechnological processes. The objective of this study was to isolate new strain of Streptomyces that produce proteolytic enzymes with novel properties and the development of the low-cost medium. An alkaline protease producer strain NRC-15 was isolated from Egyptian soil sample. The cultural, morphological, physiological characters and chemotaxonomic evidence strongly indicated that the NRC-15 strain represents a novel species of the genus Streptomyces, hence the name Strptomyces pseudogrisiolus NRC-15. The culture conditions for higher protease production by NRC-15 were optimized with respect to carbon and nitrogen sources, metal ions, pH and temperature. Maximum protease production was obtained in the medium supplemented with 1% glucose, 1% yeast extract, 6% NaCl and 100 μmol/L of Tween 20, initial pH 9.0 at 50 °C for 96 h. The current results confirm that for this strain, a great ability to produce alkaline proteases, which supports the use of applications in industry.