Self-protection of Streptomyces to ε-poly-L-lysine improves fermentation efficacy

Antimicrobial peptides (AMPs) are regarded as a promising new class of antimicrobials. In antimicrobials production by microorganisms, such as antibiotics fermentation, reducing the end-product toxicity based on the self-protection mechanism is adopted to improve the viability of the producing strain and the consequent productivity. However, such kind of strategy in AMPs fermentation is rarely used due to the unclear mechanism for protection from AMPs injury. In this study, the effects of epsilon-poly-L-lysine (epsilon-PL), a valuable AMP, on its own producer Streptomyces were investigated. epsilon-PL disrupted the membrane integrity leading to the decrease of respiratory activity and increased the oxidative stress. Due to the decrease of unsaturation ratio of fatty acid, increase of trehalose and activation of catalase (CAT), Streptomyces alleviated the injury caused by epsilon-PL. Through the enhancement of self-protective ability, the fermentation efficiency of epsilon-PL was improved by similar to 1.4-fold in Streptomyces.

Automated summary

This study investigated the effects of the antimicrobial peptide ε-PL on its producer Streptomyces. ε-PL disrupted membrane integrity and increased oxidative stress, leading to cell damage. However, Streptomyces counteracted the injury through self-protective mechanisms, resulting in improved fermentation efficiency of ε-PL.