Study of
protein and gene expression during fermentation and in response to stress using
2D and Microarrays technologies.
Dominique Kobi,
Laurence Gutfreund
TEPRAL research center, Brasseries Kronenbourg, Oberhausbergen, Strasbourg,
67037, France (dominique.kobi@tepral-fr.com)
Even if brewing yeasts are quite well adapted to specific brewing conditions, they are still sensitive to stress. Different kind of stress can be encountered during fermentation: high ethanol rate, acid washing, wort high osmolarity, pressure. In order to understand the physiological and metabolic response of yeast to such stress, two approaches have been used: protein expression by 2D electrophoresis and gene expression by microarrays. As fermentation conditions are very different for top and bottom fermenting yeasts, it was firstly obvious to compare their proteome and transcriptome under the same conditions. Then it was also essential to verify that Saccharomyces cerevisiae chips were suitable for studying brewing strains. It was then possible to study specific stress. We decided to first elucidate the impact of a high ethanol concentration stress on two type of yeast: top and bottom, and Saccharomyces cerevisiae S228c as reference. After a culture on YPG medium, different ethanol concentrations have supplemented the medium, cell samples have been taken at 0, 1, 3h after treatment and analyzed either by 2D protein electrophoresis or microarrays or both. Results will be presented here.