Flow Cytometry — A Primer for Modern Analytical Technology to Assess Yeast Culture Quality for Fermentation

Flow cytometry is an analytical technology that allows users to interrogate single cells at high speeds to provide a detailed data-rich analysis of complex cell populations. Flow cytometry can offer an effective means to quickly evaluate yeast culture integrity using a small sample to assess the complexity and underlying heterogeneity in a culture. It can assess cell viability, purity and complexity, with respect to potential contaminating species, of the culture providing a higher level of confidence in the population to be used for fermentation. This is an important problem to address in breweries where multiple domestic yeast strains are employed or where various wild strains of Saccharomyces cerevisiae as well as wild or cultured Brettanomyces species are used for fermentation. Such analysis can enhance confidence and reduce costs associated with new yeast culture purchase in commercial fermentations and promote a deeper understanding of the complexities of mixed fermentations. Lastly, flow cytometry can add new levels of analysis associated with fluorescent labeling of cell DNA content and selected cell proteins.