Screening of Bacterium Producing Amylase from the Soil and Optimization of the Condition for Enzyme Production

In order to screen a bacterium which can produce amylase,starch hydrolysis circle is used in this experiment as a screening model.The Strain B5 is achieved by screening from the soil near the starch factory.After the optimization of the condition,the capability of B5 is improved.The optimal condition is:carbon source is starch 2.0 %;nitrogen source is yeast extract 0.5 % and peptone 0.5 %;the initial pH is 6.0;and the optimum incubation temperature is 37 ℃;the appropriate load is 15 mL culture medium in 50 mL flask;the optimal time for producing amylase is 48 h;when 0.05 % MgSO4,0.05 % CaCl2,and 0.005 % FeSO4 is added to the medium,the amylase activity can be improved greatly.The amylase activity of Strain B5 in liquid fermentation can reach as high as 158.89 U/mL.The optimal reaction temperature of amylase is 42 ℃,and the optimum reaction pH of amylase is 5.0.The experimental method is simple and intuitive,and can be used to screen amylase-producing strain quickly and efficiently.