Preparation and Mutation of Protoplasts from Streptomyces caespitosus

AIM The purpose is to develop the method of the preparation of protoplasts from Streptomyces caespitosus and to screen high-yielding mutant strains by mutation of the protoplasts. METHOD The protoplasts were prepared by enzyme and irradiated with UV and laser. The mutation result was determined by HPLC. RESULTS The optimum conditions for preparing the protoplasts from Streptomyces caespitosus were summarized as follows: to cultivate the mycelia in the medium containing 1.5%Gly and 25% sucrose and to lysis the mycelia in the solution containing 5 mg/ml lysozyme,2 mg/ml snailase and 2 mg/ml cellulase in the bath of 33℃, 2 h. The positive rate of mutants irradiated with laser was higher than that with UV and two high-yielding mutants were obtained by laser irradiation whose yield is 22.2% and 23.0% higher than that of the parent strain respectively. CONCLUSION The method greatly improved the preparation of protoplasts from Streptomyces caespitosus and high-yielding mutant strains could be obtained by laser irradiation of the protoplast.