Abstract:

Abstract: Three types 60Co γ Rays are applied on the spores based on the experiments on present high-yield L7 strains to lower the cost and make the Wuyiencin more effective. In the event that 1000 grays are adopted, 98.7% of the spores die and 18.9% mutate. It shows 1000 grays of Wuyiencin are the most appropriate for testing. 78 strains out of 3,582 are selected by screening of agar blocks, and then fermented and screened once again, among which 20 strains are tested above 5000μg/ml in tilter, in which 5 strains ( i.e. C-28，C-42，C-64，C-75，C-76) are tested as to genetic stability.As a result, C-75 strain is the most stable genetically with 5528μg/ml of titer, 34.4% higher than L7 strains (4112μg/ml of liter) and therefore is determined as high-yield producing strain of Wuyiencin by 60Co γ ray mutagenesis. By contrast, the other four strains degenerate to different degrees.