Transcriptome analysis of Saccharomyces cerevisiae at the late stage of very high gravity (VHG) fermentation

DNA microarray analysis was used to investigate the expression profile of Saccharomyces cerevisiae genes in glycolysis pathway, trehalose and steroid biosynthesis and heat shock proteins (HSP) in response to harsh environment under the late stage of very high gravity (VHG) fermentation. The data show that only a few genes (GPM2, PGM1, GAL10 and PGM1) involved in glycolysis pathway and trehalose biosynthesis were up-regulated. Five genes that encode heat shock proteins (HSP26, HSP10, HSP42, HSP78 and HSP82) were up-regulated. Among these five genes, there was a strong expression increase of about 84-fold for HSP26. The results of this study revealed adverse VHG fermentation conditions stress response pattern and suggested interesting information about the mechanisms involved in adaptation of cells to the complex VHG fermentation environment. This identification of genes provides information that will help to genetically modify yeast to further maintain the fermentation fitness and improve its fermentation capacity and process.