Inhibition of Saccharomyces cerevisiae by slow release of propyl paraben from a polymer coating

Abstract

The inhibition of Saccharomyces cerevisiae by slow release of propyl paraben from a styrene-acrylate copolymer coating was examined and compared with the inhibition by direct addition of propyl paraben. Under slow release condition, a slow but continuous microbial inhibition was observed, whereas a cell outgrowth was observed under direct addition condition after a sufficient incubation time. S. cerevisiae cells isolated from the culture under direct addition condition were more tolerant of propyl paraben than cells isolated from the culture under slow release condition. The equilibrium propyl paraben concentrations under both conditions were 150 ppm. The release kinetics of propyl paraben from the coating at 30°C was found to be controlled by Fickian diffusion within the coating. The estimated partition and diffusion coefficients were 4.65 × 10-3 and 2.01 × 10-10 cm2/s, respectively.