Improvement of the slide culture technique for the assessment of yeast viability

Abstract

This work aimed to improve the slide culture technique (SCT) for the assessment of yeast viability. Thus, all the steps of the SCT were standardized: a sample of 20 μL containing 1 × 105 cells/mL was placed in a ~ 20 × 20 mm YPD agar block and incubated for 16–24 h, at 25°C. It was proposed the use of calcofluor white (CFW) to facilitate the microscopic observation of yeast cells. The viability of cell populations in different physiological states (healthy, ethanol stressed and starved cells), assessed by SCT (without or with CFW), did not differ significantly (p < 0.01). In addition, the viability of healthy and ethanol stressed cells determined by the SCT and the standard plate count technique (PCT) did not differ significantly (p < 0.01). In conclusion, the improved SCT is a fast and reliable alternative to PCT for the evaluation of yeast viability in research and in the industry. Copyright © 2017 The Institute of Brewing & Distilling.