SO2 and copper tolerance exhibit an evolutionary trade-off in Saccharomyces cerevisiae.

Copper tolerance and SO2 tolerance are two well-studied phenotypic traits of Saccharomyces cerevisiae. The genetic bases of these traits are the allelic expansion at the CUP1 locus and reciprocal translocation at the SSU1 locus, respectively. Previous work identified a negative association between SO2 and copper tolerance in S.

Analysis of Transcriptomic Response to SO by Oenococcus oeni Growing in Continuous Culture.

To successfully complete malolactic fermentation (MLF), Oenococcus oeni must overcome wine stress conditions of low pH, high ethanol, and the presence of SO. Failure to complete MLF may result in detrimental effects to the quality and stability of the resulting wines. Research efforts to date have focused on elucidating the mechanisms and genetic features that confer the ability to withstand low pH and high ethanol concentrations on O.

Aromatic Higher Alcohols in Wine: Implication on Aroma and Palate Attributes during Chardonnay Aging.

The higher alcohols 2-phenylethanol, tryptophol, and tyrosol are a group of yeast-derived compounds that have been shown to affect the aroma and flavour of fermented beverages. Five variants of the industrial wine strain AWRI796, previously isolated due to their elevated production of the 'rose-like aroma' compound 2-phenylethanol, were characterised during pilot-scale fermentation of a Chardonnay juice. We show that these variants not only increase the concentration of 2-phenylethanol but also modulate the formation of the higher alcohols tryptophol, tyrosol, and methionol, as well as other volatile sulfur compounds derived from methionine, highlighting the connections between yeast nitrogen and sulfur metabolism during fermentation.

Evaluation of Wine Yeast Competitive Fitness in Enologically Relevant Environments by Barcode Sequencing.

When a wine yeast is inoculated into grape juice the potential variation in juice composition that confronts it is huge. Assessing the performance characteristics of the many commercially available wine yeasts in the many possible grape juice compositions is a daunting task. To this end we have developed a barcoded wine yeast collection to facilitate the task of performance assessment that will contribute to a broader understanding of genotype-phenotype relations.

Whole Genome Comparison Reveals High Levels of Inbreeding and Strain Redundancy Across the Spectrum of Commercial Wine Strains of Saccharomyces cerevisiae.

Humans have been consuming wines for more than 7000 yr . For most of this time, fermentations were presumably performed by strains of Saccharomyces cerevisiae that naturally found their way into the fermenting must . In contrast, most commercial wines are now produced by inoculation with pure yeast monocultures, ensuring consistent, reliable and reproducible fermentations, and there are now hundreds of these yeast starter cultures commercially available.

Impacts of variations in elemental nutrient concentration of Chardonnay musts on Saccharomyces cerevisiae fermentation kinetics and wine composition.

Chardonnay, being the predominant white wine-grape cultivar in the Australian wine sector, is subject to widely varying winemaking processes with the aim of producing a variety of wine styles. Therefore, juice composition might not always be ideal for optimal fermentation outcomes. Our aim was to better understand the composition of Chardonnay juice and how compositional parameters impact on fermentation outcomes.

Occurrence of hydrogen sulfide in wine and in fermentation: influence of yeast strain and supplementation of yeast available nitrogen.

Hydrogen sulfide (H₂S) is a powerful aroma compound largely produced by yeast during fermentation. Its occurrence in wines and other fermented beverages has been associated with off-odors described as rotten egg and/or sewage. While the formation of hydrogen sulfide (H₂S) during fermentation has been extensively studied, it is the final H₂S content of wine that is actually linked to potential off-odors.