Induction of the oxidative stress response has been described under many physiological conditions in Saccharomyces cerevisiae, including industrial fermentation for wine yeast biomass production where cells are grown through several batch and fed-batch cultures on molasses. Here, we investigate the influence of aeration on the expression changes of different gene markers for oxidative stress and compare the induction profiles to the accumulation of several intracellular metabolites in order to correlate the molecular response to physiological and metabolic changes. We also demonstrate that this specific oxidative response is relevant for wine yeast performance by construction of a genetically engineered wine yeast strain overexpressing the TRX2 gene that codifies a thioredoxin, one of the most important cellular defenses against oxidative damage. This modified strain displays an improved fermentative capacity and lower levels of oxidative cellular damages than its parental strain after dry biomass production.
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Acknowledgments This work was supported by grants AGL2002-01109, AGL 2005-00508 from the “Ministerio de Educación y Ciencia” (MEC), and GRUPOS03/012 and GVACOMP2007-157 from the “Generalitat Valenciana”. R.P.-T. was supported by a predoctoral fellowship from “Generalitat Valenciana” and R.G.-P. is a predoctoral fellow of the I3P program of “Consejo Superior de Investigaciones Científicas” (Spain). We thank Dr. E. Garre for critical reading of the manuscript.
- Fermentative capacity
- Genetic improvement
- Oxidative stress response
- Wine yeast propagation