Comparative polygenic analysis of maximal ethanol accumulation capacity and tolerance to high ethanol of cell proliferation in yeast. Saccharomyces cerevisiae CBS 1585

In this work, we have for the first time applied polygenic analysis to the complex trait of high ethanol accumulation capacity in yeast fermentation. We have used 250 mL semi-static fermentations with 33% glucose resulting in routine accumulation of ≥17% ethanol. Using the same parent strains and segregants we also determined tolerance of cell proliferation to high ethanol as generally measured on solid nutrient plates. This revealed that the two complex traits have a partially different genetic basis. We identified three genes specifically linked to maximal ethanol accumulation capacity, revealing the importance of DNA damage repair in the capacity of yeast to accumulate high ethanol levels. In addition, our results show that the genetic basis of tolerance of cell proliferation to high ethanol is dependent on the genetic background of the yeast strain.