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.

聚-L-赖氨酸（Poly-L-lysine, PL）是一种同型氨基酸聚合物，在食品、医药及化妆品行业具备广泛的应用潜力。但受限于较低的生产效率，其生产成本居高不下，进一步的规模化应用受到制约。本研究采用组合菌株选育策略，成功获得一株高产突变株——白色链霉菌（Streptomyces albulus）GS114，该菌株的胞外L-赖氨酸摄取能力得到显著增强。随后，本研究在补料分批发酵（fed-batch fermentation）工艺中对L-赖氨酸补加条件进行了系统优化，最终使PL的发酵产量达到73.07 g/L。为揭示添加L-赖氨酸可提升白色链霉菌GS114 PL产量的内在机制，本研究开展了比较转录组学分析（comparative transcriptomics analysis）。实验分别从两个分批发酵批次的36小时时点采集样本：一组发酵批次未添加L-赖氨酸，另一组则在发酵至24小时时补加4 g/L的L-赖氨酸。