Hanseniaspora in wine-making: their genetic modification and potential role in acid modulation

In the challenge of transforming waste into useful products that can be re-used in a circular economy perspective, winery by-products can be considered as a source of potentially bioactive molecules such as polyphenols. The wine industry generates each year 20 million tons of by-products. Kombucha fermentation is an ancestral process which allow to increase the biological properties of tea by the action of a microbial consortium formed by yeasts and bacteria called SCOBY. It belongs to the field of healthy food for which the interest of consumers is growing. The objective of this work was to propose a new functional beverage made from winemaking by-products fermented by a Kombucha SCOBY.

Glutathione plays a key role in preventing some oxidative processes during winemaking. This molecule limits the must enzymatic oxidation, reacts with caffeic acid and generates a colourless compound that prevents subsequent browning. It also has a protective effect on wine aroma, preventing the oxidation of the volatile compounds with a high sensory impact.

Several factors like vineyard site, climate, grape variety, ripeness, physical health of the grapes and pest management influence the populations of indigenous yeasts on grapes and later on in spontaneous fermentations.

Grapevine cultivars are vegetatively propagated to maintain their varietal characteristics. This process of multiplication leads to spontaneous somatic mutations that can eventually generate a variant phenotype, of potential interest for cultivar improvement and innovation. However, regardless their phenotypic effect, somatic mutations stack in the genome, and they can be used to reveal the origin and dissemination history of ancient cultivars. Here, a stringent somatic variant calling over whole genome resequencing data from 35 ‘Tempranillo Tinto’ clones or old vines from seven Iberian winemaking regions revealed 135 single nucleotide variations (SNVs) shared by some of the clonal lines.

Historical phenology records have indicated that advances in key developmental stages such as budburst, flowering and veraison are linked to increasing temperature caused by climate change. Using phenological models the timing of grapevine development in response to temperature can be characterized and projected in response to future climate scenarios.
We explore the development and use of grapevine phenological models and highlight several applications of models to characterize the timing of key stages of development of varieties, within and between regions, and the result of projections under different climate change scenarios.