Progress in biosynthesis of epsilon-poly-L-lysine and genetic transformation for epsilon-poly-L-lysine producer--a review
ε-聚赖氨酸生物合成及其产生菌遗传转化研究进展

Epsilon-Poly-L-lysine (epsilon-PL) is a polymer with strong antimicrobial activity and consists of 25-35 L-lysine monomers linked via epsilon-amino-alpha-carboxyl peptide bond. This polymer is one of only two homo-poly (amino acid) polymers known in nature. To date, the biosynthesis mechanism of epsilon-PL was remained unclear. Recently, epsilon-PL synthetase was identified as a nonribosomal peptide synthetase and it utilized L-lysine to synthesize epsilon-PLs of various chain length by iteratively condensing reaction, which was similar to type I polyketide synthase and was not determined by epsilon-PL-degrading enzyme. Meanwhile, the shutter vectors pLAE001 and pLAE003, special for epsilon-PL producer have been constructed, which is significant for studying epsilon-PL biosynthesis. In this review, the biosynthesis of epsilon-PL and the genetic transformation were introduced. Also, the study in our group was presented and the views related to e-PL study were raised. Finally, the prospect of application of combinational biosynthesis in epsilon-PL-producing strain improvement was also discussed considering epsilon-PL synthetase is a nonribosomal peptide synthetase containing several modules.