Characterization of solvent，detergent and oxidizing agent stable protease from isolated Antarctic marine Streptomyces sp.XE-1

Abstract:

Abstract:［Objective］A polar marine actinobacterium (XE-1) was selected and used to produce a protease with special characteristics.［Methods］The XE-1 was identified as Streptomyces based on morphological，biochemical and molecular characterizations (16S rRNA gene sequence analysis)．The protease was purified by 3 purification steps，including ethanol precipitation，ion exchange and gel chromatography．Its apparent molecular mass was estimated by SDS-PAGE.［Results］A solvent，detergent and oxidizing agent stable alkaline serine protease (with a low weight molecular，14 kDa by SDS-PAGE)，secreted by strain XE-1，was purified and characterized．The protease was stable in the pH range between 5 and 10，with optimal pH 8.2 and optimal temperature 55℃ ．Km and Vmax towards casein activity were 1.9 mg/mL and 973 U/mL，respectively．The protease was more active and stable in various hydrophilic organic solvents (such as dimethylformamid and toluene)．Moreover，it was also active and stable in bleaching agents (such as hydrogen peroxide); and stable in denaturant agents (such as urea and guanidine hydrochloride) at the concentration from 0.2 mol/L to 4 mol/L，which were the new characteristics． ［Conclusion］These biochemical characteristics suggest this enzyme has the potential value in numerous industrial applications.