Purification and properties of alkaline protease from B.licheniformis 2709

The alkaline protease was purified from B·licheniformis 2709 by alcohol precipitation,ammonium sulphate precipitation,DEAE ion exchange chromatography,and gel layer chromatography and the purified alkaline was demonstrated to be electrophoretic by SDS-PAGE.The results indicated that the enzyme activity of purified protease was 61069 U·mg-1 with final purification factor,activity recovery factor and deamidation reate of 38.7,19.3%,and 20.9%,respectively.The optimal conditions for the highest activity of alkaline protease were as follows:pH 10.0,and temperature 50℃.After incubation at 40℃ for 2h,the residual activity of the enzyme was above 80%,and the enzyme was relatively stable at pH 8-11.