Rational screen of high Kelimycin-producing strain by combined conventional mutagenesis and high-throughput screen method

Abstract:

Abstract:Kelimycin，is a new macrolide antibiotic drug obtained through genetic engineering approaches．With 4 "-Oisovalerylspiramycins as the major components，was produced by genetically engineered Streptomyces spiramyceticus transformed with 4 " -O-acyltransferase gene from S． mycarofaciens．［Objective］ Improve the efficiency of strain fermentation，to meet the needs of industrial production．［Methods］ The enhanced kelimycin-producing strain was obtained by applying various conventional mutagenesis approaches，and high-throughput screen methods，including protoplast mutagenesis by ultraviolet，mutagenesis by diethyl sulfate and UV-reactivation，valine content resistance screen and enrichment of improved strains．A strategy for positive mutant enrichment was developed after mutagenesis and before high-throughput screen．［Results］ Finally，the high-producing strain WSJ-1-7-49-133-82-18-43 was obtained and its potency in shake flask increased by 56% compared to the original strain． The potency in 500 L pilot fermenter increased by 61%．［Conclusion］This study shows that the screening industrial production strains can be enhanced effectively by combining multiple conventional mutagenesis and high-throughput screen methods.