Genome shuffling and ribosome engineering of Streptomyces virginiae for improved virginiamycin production

The production of virginiamycin (VGM) from Streptomyces virginiae was improved by genome shuffling and ribosome engineering companied with a high-throughput screening method integrating deep-well cultivation and the cylinder-plate detecting. First, a novel high-throughput method was developed to rapidly screen large numbers of VGM-producing mutants. Then, the starting population of genome shuffling was obtained through ultraviolet (UV) and microwave mutagenesis, and four mutants with higher productivity of VGM were selected for genome shuffling. Next, the parent protoplasts were inactivated by UV and heat when a fusant probability was about 98%. Streptomycin resistance was used as an evolutionary pressure to extend positive effects on VGM synthesis. Finally, after five rounds of genome shuffling, a genetically stable strain G5-103 was obtained and characterized to be able to yield 251 mg/L VGM, which was 3.1- and 11.6-fold higher than that of the mutant strain UV 1150 and the wild-type strain, respectively.