Studying the impact of cell age on the yeast growth behaviour of Saccharomyces pastorianus var. carlsbergensis by magnetic separation

Despite the fact that yeast is a widely used microorganism in the food, beverage, and pharmaceutical industries, the impact of viability and age distribution on cultivation performance has yet to be fully understood. For a detailed analysis of fermentation performance and physiological state, we introduced a method of magnetic batch separation to isolate daughter and mother cells from a heterogeneous culture. By binding functionalised iron oxide nanoparticles, it is possible to separate the chitin-enriched bud scars by way of a linker protein. This reveals that low viability cultures with a high daughter cell content perform similarly to a high viability culture with a low daughter cell content. Magnetic separation results in the daughter cell fraction (>95%) showing a 21% higher growth rate in aerobic conditions than mother cells and a 52% higher rate under anaerobic conditions. These findings emphasise the importance of viability and age during cultivation and are the first step towards improving the efficiency of yeast-based processes.

Automated summary

Despite the wide use of yeast in various industries, the impact of viability and age distribution on cultivation performance is not fully understood. In this study, a magnetic batch separation method was used to isolate daughter and mother cells from a heterogeneous culture, revealing that low viability cultures with high daughter cell content perform similarly to high viability cultures with low daughter cell content. The separated daughter cells showed higher growth rates than mother cells in both aerobic and anaerobic conditions. These findings highlight the importance of viability and age in yeast cultivation and lay the foundation for improving yeast-based processes.