Bactericidal Kinetics of ε-Poly-L-Lysine Based on Metabolic Activity
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
ε-Poly-L-lysine (ε-PL) is a natural and safe food preservative with a broad-spectrum and strong antimicrobial activity. In the present study, Escherichia coli and Bacillus subtilis were used to investigate their metabolic activity before and after treatment with the fluorescent probe, 5-cyano-2,3-ditolyl tetrazolium chloride. The relative activity was calculated to investigate the bactericidal effect of ε-PL. Both the Linear and Weibull models were used to describe the bactericidal dynamics of ε-PL. For E. coli in liquid culture, a low-concentration of ε-PL (0.005%) applied for 15 and 120 min decreased metabolic activity of E. coli to 86.33% and 73.44% of its original activity, respectively. When a relative higher concentration of 0.025% was used, E. coli metabolic activity was only 21.06% after 15 min treatment and 3.61% at 120 min treatment. The bactericidal effect of ε-PL on B. subtilis was similar to that on E. coli. The kinetic analysis revealed that the fit of the Linear model was low, with an R2 value <0.70. By contrast, the Weibull model showed a better fit in all test concentrations of ε-PL against E. coli and B. subtilis, with an R2 value >0.97. The findings indicate that using metabolic activity as an index, the Weibull model can accurately fit the bactericidal kinetics of ε-PL.
