Streptomyces albulus for the production of Poly-L-lysine
Poly-L-lysine (PL) is a homo-amino acid polymer with broad potential applications in the food, pharmaceutical and cosmetic industries. However, its low productivity results in high production costs, limiting further application. In this study, a cocktail strain breeding strategy was employed to generate a high-yield mutant, Streptomyces albulus GS114, with enhanced extracellular L-lysine uptake capability. Subsequently, the L-lysine feeding condition was systematically optimized in fed-batch fermentation, achieving PL production reaching 73.07 g/L. To reveal the reasons for L-Lysine addition promoting the PL production in S. albulus GS114, a comparative transcriptomics analysis was performed. The samples were collected from two batch fermentation at 36 h. One batch fermentation was carried out without L-lysine addition and the other was added 4 g/L L-lysine at 24 h.