Mutation screening of Streptomyces 702 by NTG and LiCl.

Purpose: To screen out a Streptomyces 702 strain of high yield of New Ag-antibiotics 702.Methods: Gentamycin-resistance mutational labelling selection model with Streptomyces 702 strain ws used as the experimental material and Gentamycin as sensitive antibiotic to screening high-yield mutants.The Streptomyces 702 spores was treated by NTG-LiCl composite mutation.Results: The results showed that the gentamycin-resistance mutational frequency of the streptomyces 702 treated by NTG-LiCl with 90 min utes was up to 19.46% and the lethal rate was 71.56% .High New Ag-antibiotics 702-producing mutant 13-18-52 was isolated in the screening experiments,and its yield of New Ag-antibiotics 702 reached 1946μg/mL.which was 37.43% higher than that produced by its parent strain.Conclusion: The Streptomyces 702 strain of high New Ag-antibiotics 702 could be obtained by NTG-LiCl composite mutation and resistance-chemical mutational labelling selection model.