Mutagenesis of Alkaline Protease-Producing Marine Strain and Enzyme Properties

[Objective] The aim of the research was to select alkaline protease-producing strains and provide basis for the application in production.[Method] An alkaline protease-producing strain was isolated from the sea water and sea mud collected from Qingdao coastal area.After ultraviolet mutagenesis and microwave mutagenesis,a target strain ZR-58-3-1-3 was obtained.The enzyme activity and enzyme properties of the strain were determined preliminarily.[Result] Enzyme activity of the selected strain reached 145 U/ml.After the compound mutagenesis,enzyme activity of the fermentation liquid of strain ZR-58-3-1-3 reached 775 U/ml,which was about 4.3 times higher than that of the original strain.The optimal temperature for alkaline protease produced by strain ZR-58-3-1-3 was 45 ℃,and the optimal pH was 8.5,suggesting that it belongs to moderate temperature protease with relatively high thermal stability.[Conclusion] Strain ZR-58-3-1-3 has stable alkaline protease production performance and can be used as an alkaline protease-producing mutant strain.