Antimicrobial Assay of Metal Ions Using Yeast and Its Relevance to Food Preservation

The increasing occurrence of antimicrobial resistance in recent years has spurred research to produce new antimicrobial compounds. However, there is currently a lack of a rapid, simple, and quantitative assay to determine the antimicrobial characteristics of new antimicrobial compounds. In this study, we demonstrated that a simple water displacement apparatus can be used to determine the effects of various metal ions on the cell viability of a model organism Saccharomyces cerevisiae (S. cerevisiae) by monitoring the volume of CO2 (VCO2) released. Analysis on the effect of different metal ions on S. cerevisiae demonstrated a linear relationship between VCO2 and the reduction potentials and a linear–logarithmic relationship between VCO2 and the metal/ligand binding constant indicating this measurement's accuracy and quantitative nature. Due to its speed, simplicity, and accuracy, this water displacement method has the potential to be used as a pre-screening method to facilitate the rapid quantification and development of more effective antimicrobial agents for various applications including antimicrobial food preservation and packaging.