Streptomyces sp. K47 alkaline proteases: partial purification and analysis by zymography

Abstract

Microbial enzymes are used as organic catalysts in different industrial processes. In this study, we aimed to produce and investigate alkaline proteases from a novel actinobacterium strain isolated from a Black Sea marine sediment. The optimal production conditions for Streptomyces sp. K47 alkaline proteases was 4-days incubation at 28ºC in a salt-free medium buffered with 50 mM Tris-HCl buffer (pH 9.0) and containing glucose (1.0%, w v^-1) and yeast extract (0.5%, w v^-1). The enzyme solution was partially purified using (NH4)₂SO₄ precipitation (40-70%). After desalting, it was purified 1-84 fold with a recovery of 19.42%. Zymogram analyses revealed the presence of more than one protease enzyme. The enzyme solution exhibited maximum activity at pH 9.0 and 37ºC, remaining stable after a 2-hour incubation at all tested conditions. Streptomyces sp. K47 has the potential to be used in industrial processes because of its ability to produce multiple protease enzymes displaying stability in a broad pH and temperature range.