Omics analysis reveals the mechanism of metabolic oscillation during
continuous VHG ethanol fermentation by Saccharomyces cerevisiae
Abstract
During continuous very high gravity (VHG) fermentation, yeast cells
exhibit sustained oscillation of residual glucose, ethanol, and biomass,
which remains a fundamental and unanswered question associated with
product inhibition. In this study, the oscillating process was
characterized through transcriptome and metabolome analysis in one
sinusoid cycle. By integrating analysis of 26 metabolites and 90 genes
related to carbon metabolism, the results confirmed that fermentation
oscillation could be attributed to intercellular metabolic oscillation
with phase difference of sinusoidal waveform. Furthermore, expression
changes of stress response genes indicated that dynamic ethanol
inhibition was a primary factor responsible for the oscillation of
metabolism. This study not only contributes to elucidation of the
mechanism of oscillating fermentation through strong product inhibition,
but also provides new understanding of other fermentation processes in
an unsteady state.