Growth Inhibition Mode of Action of Selected Benzoic Acid Derivatives against the Yeast Pichia anomala

• Published in: Journal of food protection 2009-04, Vol.72 (4), p.791-800
• Main Author: Koczon, P
• Format: Article
• Language: English
• Subjects: Acids; antifungal properties; Antimicrobial agents; Benzoates - pharmacology; benzoic acid; Biological and medical sciences; Chemical synthesis; Chemicals; Dose-Response Relationship, Drug; Energy consumption; Equilibrium; food contamination; Food industries; Food Microbiology; Food Preservation; food preservatives; Food Preservatives - pharmacology; Food safety; Food science; food spoilage; Fundamental and applied biological sciences. Psychology; Hansenula anomala; mechanism of action; Microorganisms; Mode of action; Organic acids; organic acids and salts; Pichia - drug effects; Pichia anomala; Saccharomyces; Time Factors; Turbidity; Yeast; Yeasts; Yeasts - drug effects; Zinc; Zygosaccharomyces
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-72.4.791

Three benzoic acid derivatives (zinc p-iodobenzoate, zinc p-hydroxybenzoate, and zinc p-aminobenzoate) were synthesized and tested chemically and microbiologically in order to explain their mode of action against the yeast Pichia anomala. The yeast strains were cultivated in batch culture of chemically defined minimal medium (control) and with the addition of the studied compound at concentrations of 0.103 to 0.166% (wt/vol). The growth of microorganisms, H+ concentration, and the concentrations of both dissociated and undissociated forms of the appropriate weak acid in the medium were monitored at 1-h intervals during 24 h of incubation. The inhibitory effect of each compound on the growth of microorganisms was calculated based on measurement of optical density at 600 nm turbidity. The K parameter, defined as the ratio of the concentration of undissociated weak acid to the number of microorganisms in the medium, was determined. The K value is related to the degree of growth inhibition and provides new insight into the mode of action of weak organic acids against the studied yeasts. The buffering capacity of the chemicals studied was also found to be an inhibition parameter associated with microbial growth. Greater buffer capacity of a given compound reduced changes in the pH value of the medium, resulting in changes to antimicrobial effectiveness.