Metabolomic Analysis of Antimicrobial Mechanisms of ε-Poly-l-lysine on Saccharomyces cerevisiae

Abstract

ε-Poly-L-lysine (ε-PL), a naturally occurring amino acid homopolymer, has been widely used as a food preservative. However, its antimicrobial mechanism has not been fully understood. This study investigated the antimicrobial mode of action of ε-PL on a yeast, Saccharomyces cerevisiae. When treated with ε-PL at the concentration of 500 μg/mL, cell mortality was close to 100% and the phospholipid bilayer curvature, pores, and micelles on the surface of S. cerevisiae were clearly observed by scanning electron microscopy (SEM). At the level of 200 μg/mL, ε-PL significantly inhibited the cell growth of S. cerevisiae. When treated with 50 μg/mL ε-PL, the yeast cell was able to grow but the cell cycle was prolonged. A significant increase in cell membrane permeability was induced by ε-PL at higher concentrations. Metabolomics analysis revealed that the ε-PL stress led to the inhibition of primary metabolic pathways through the suppression of the tricarboxylic acid cycle and glycolysis. It is therefore proposed that the microbiostatic effect of ε-PL at lower levels on S. cerevisiae is achieved by inducing intracellular metabolic imbalance via disruption of cell membrane functions. Moreover, the results suggested that the antimicrobial mechanism of ε-PL on S. cerevisiae can in fact change from microbiostatic to microbicidal when the concentration of ε-PL increased, and the mechanisms of these two modes of action were completely different.

The inhibition mechanism of ϵ‐polylysine against Bacillus cereus emerging in surimi gel during refrigerated storage

“…As the concentrations were increased, more obvious changes appeared on the cell surfaces. These findings were consistent with that of Bo et al, 26 who studied the effects of -PL on Saccharomyces cerevisiae cells. Their results indicated that -PL could cause many voids to appear on the surfaces of Saccharomyces cerevisiae cells.…”

The Antimicrobial Mechanism of Action of Epsilon-Poly- l -Lysine

“…10). Because ε-PL interacts more readily with negatively charged headgroups, it has a relatively low toxicity against mammalian cells (8) and yeast cells (3,45), and differences in susceptibility among microorganisms could be caused by differences in membrane composition. For example, the membrane of L. innocua contains lysine-derivatized phosphatidylglycerol and lysylcardiolipin (19,46,47).…”

Metabolomic Analysis and Mode of Action of Metabolites of Tea Tree Oil Involved in the Suppression of Botrytis cinerea

“…For example, the activity of amphotericin B against C. albicans can be attributed to changes in metabolite production (Cao et al, 2013). Another study found that the microbiostatic effect of ε-Poly-L-lysine on Saccharomyces cerevisiae is achieved by breaking the balance of intracellular metabolites due to disruptions in cell membrane function (Bo et al, 2014). Finally, a metabolomics approach was used to demonstrate that cinnamaldehyde changes the metabolism of E. coli by interacting with different biochemical targets (Mousavi et al, 2016).…”