Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling during ethanol fermentation

Abstract EN

Objectives: To improve ethanolic fermentation performance of self-flocculating yeast, difference between a flocculating yeast strain and a regular industrial yeast strain was analyzed by transcriptional and metabolic approaches.

Results: The number of down-regulated (industrial yeast YIC10 vs.

flocculating yeast GIM2.71) and up-regulated genes were 4503 and 228, respectively.

It is the economic regulation for YIC10 that non-essential genes were down-regulated, and cells put more ‘‘energy” into growth and ethanol production.

Hexose transport and phosphorylation were not the limiting-steps in ethanol fermentation for GIM2.71 compared to YIC10, whereas the reaction of 1,3-disphosphoglycerate to 3-phosphoglycerate, the decarboxylation of pyruvate to acetaldehyde and its subsequent reduction to ethanol were the most limiting steps.

GIM2.71 had stronger stress response than non-flocculating yeast and much more carbohydrate was distributed to other bypass, such as glycerol, acetate and trehalose synthesis.

Conclusions: Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling will provide clues for improving the fermentation performance of GIM2.71.