Abstract: ε-Poly-L-lysine (ε-PL) is a novel biopolymer consisting of 25–35 L-lysine residues, which is formed by the dehydration condensation of ε-NH2 and α-COOH. ε-PL possesses many excellent characteristics, such as antimicrobial activity, edibility, water solubility, biodegradability, thermostability and nontoxicity. As a natural and safe food preservative, ε-PL possesses many excellent advantages such as thermal stability, edibility, water solubility, degradability, and broad-spectrum antibacterial activity and has been successfully utilized in Japan, South Korea, the United States, China and other countries. ε-PL is usually produced by fermentation with Streptomyces albulus, and improving ε-PL-producing stains is crucial for enhancing ε-PL production and reducing costs. At present, researchers have obtained microbial strains capable of producing high levels of ε-PL by using physicochemical mutagenesis, ribosome engineering, genome shuffling, genetic engineering and other methods. This review introduces the mechanism of ε-PL biosynthesis and recent progress in strain improvement for the production of ε-PL, and gives an overview of the fermentation process of ε-PL. Finally, this review concludes with an outlook on future research directions. We hope that this review can help promote strain improvement for green biological manufacturing of ε-poly-L-lysine.

Key words: ε-poly-L-lysine; breeding; ribosome engineering; genetic engineering; Streptomyces albulus