Evaluation of different nitrogen sources on growth and fermentation performance for enhancing ethanol production by wine yeasts.

The utilization of grape juice from low oenological value grape varieties for bioethanol production represent an alternative for diversification and value addition in viticulture. Optimizing Very High Gravity (VHG) fermentation can significantly increase ethanol productivity while reducing water and energy consumption. In this study, the impact of different nitrogen sources on growth and fermentative performance of locally selected yeast strains was investigated.

Hybridization and spore dissection of native wine yeasts for improvement of ethanol resistance and osmotolerance.

Global warming has a significant impact on different viticultural parameters, including grape maturation. An increment of photosynthetic activity generates a rapid accumulation of sugars in the berry, followed by a dehydration process which leads to a higher concentration of soluble solids. This effect is exacerbated by current viticultural practices which favor the harvest of very mature grapes to obtain wines with sweet tannins.

Construction of low-ethanol-wine yeasts through partial deletion of the Saccharomyces cerevisiae PDC2 gene.

We propose an alternative GMO based strategy to obtain Saccharomyces cerevisiae mutant strains with a slight reduction in their ability to produce ethanol, but with a moderate impact on the yeast metabolism. Through homologous recombination, two truncated Pdc2p proteins Pdc2pΔ344 and Pdc2pΔ519 were obtained and transformed into haploid and diploid lab yeast strains. In the pdc2Δ344 mutants the DNA-binding and transactivation site of the protein remain intact, whereas in pdc2Δ519 only the DNA-binding site is conserved.

Selection of non-Saccharomyces yeasts to be used in grape musts with high alcoholic potential: a strategy to obtain wines with reduced ethanol content.

Ethanol content of wine has increased over the last decades as consequence of searching phenolic maturity, requiring increased grape maturity. This may result in the production of wines with excessive alcohol levels (sometimes more than 15% (v/v)), sluggish and stuck fermentations and excessive volatile acidity. Many strategies to reduce ethanol in wines are being studied, and microbial methods have some additional advantages.