Selection of Streptomyces roseosporus strain with high yield by the inactivated parental strain protoplasts fusion

摘要

[Objective] To select the daptomycin-producing strain with high yield. [Method] The protoplast of Streptomyces roseosporus SDDT57 was killed by ultraviolet (Wavelength 253 nm, irradiation distance 30 cm) for 8 min, and that of Streptomyces roseosporus SUDT57 was killed by heating (75°C) for 60 min. Then both the killed protoplasts were fused in PEG. The strain with high yield was isolated from the fused protoplasts. [Result] The strain with the highest yield was named S. roseosporus SF06. The Shake flask fermentation was performed with capric acid. The production was improved to 113.74 mg/L, which was 2.46 and 2.47 times that of the two original strains respectively. [Conclusion] It is viable to select daptomycin-producing strain with high yield by the inactivated parental strain protoplasts fusion. This study provides much for the next research on Genome shuffling of Streptomyces roseosporus.