Effects of ε-Poly-l-lysine on the cell wall of Saccharomyces cerevisiae and its involved antimicrobial mechanism

ε-Poly-l-lysine (ε-PL) is widely used as an antibacterial agent because of its broad antimicrobial spectrum. However, the antimicrobial mechanism of ε-PL against Saccharomyces cerevisiae (S. cerevisiae) is only vaguely described. Especially, it is widely accepted that membrane disruption is its main antimicrobial mode of action, but its effect on the cell wall remains unclear. In this study, the effects of ε-PL on cell wall of S. cerevisiae were investigated, and the possible action mode of ε-PL on the cell wall was discussed. The results showed that ε-PL affected significantly the cell wall composition such as β-1, 3-glucan, mannosylphosphate and chitin, and caused cell wall more fragile. The cell wall permeability was significantly increased. Furthermore, ε-PL induced the intracellular accumulation of reactive oxygen species (ROS), as well as lead to DNA fragmentation. These results indicate that ε-PL may have a complicated antimicrobial mode of action with multi-target mechanisms against S. cerevisiae cells.