Combining Genome Shuffling and Interspecific Hybridization Among Streptomyces Improved ε-Poly-l-Lysine Production

Here we first improved the ε-PL productivity in five species of wild-type strains in Streptomyces ( Streptomyces padanus , Streptomyces griseofuscus , Streptomyces graminearus , Streptomyces hygroscopicus , and Streptomyces albulus ) by genome shuffling. Then all the shuffled strains were suffered from an interspecific hybridization through stochastic protoplast fusion. One hybrid designated FEEL-1 was selected by morphology and spore color with ε-PL production of 1.12 g/L in shake flask, about 2.75-fold higher than that in wild types. The ε-PL production of FEEL-1 was then obtained as 24.5 g/L in fed-batch fermentation, which was 63–81 % higher than those in shuffled strains. Random amplified polymorphic DNA revealed that FEEL-1 was probably hybridized from S. padanus , S. griseofuscus , and S. albulus . Activities of several enzymes in FEEL-1 (hexokinase, phosphoenolpyruvate carboxylase, aspartokinase, and citrate synthase) were more active than those in shuffled strains, which was a possible reason for the enhancement of ε-PL production. This research highlights the importance of genome shuffling along with interspecific hybridization as a new breeding strategy for improving phenotype of industrial strains.