Abstract: In order to improve the ε-poly-lysine (ε-PL) production of Streptomyces griseofuscus, intergeneric hybridization between S. griseofuscus and Brebvibacterium flavum for enhanced level of the endogenous precursor lysine in the cells was investigated for the first time in this study. One hybrid designated LS-32 was selected by using melanin as genetic marker, which produced 2.82 g/L of ε-PL in a shake flask, 1.73 folds as high as that of S. griseofuscus. In fed-batch fermentation, the ε-PL production of LS-32 was 56.4 g/L, which was increased by 38.9% as compared to that of S. griseofuscus. Randomly amplified polymorphic DNA (RAPD) analysis confirmed the intergeneric hybridization between S. griseofuscus and B. flavum. The activities of several key enzymes in LS-32 were greater than in S. griseofuscus. Furthermore, the concentrations of intracellular amino acids such as Asp, Glu and Arg in LS-32 were much higher than in S. griseofuscus. This research proves the importance of enhancing the endogenous lysine for improving ε-PL production and that intergeneric hybridization is a new breeding strategy for ε-PL production.

Key words: ε-poly-lysine, endogenous lysine, intergeneric hybridization, fermentation