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

Grape growers around the world are seeking to reduce their reliance on herbicides. However, traditional alternatives to chemical weed control do not always integrate seamlessly into established vineyard operations. Employing nonchemical weed management often requires trellis alterations, purchasing or hiring new equipment, and depending on region, may significantly increase tractor passes required to reach desired level of weed control. Critical thinking and thoughtful strategies are necessary to minimize expenditures and maintain quality during the transition away from herbicides. In this trial, irrigation was installed underground in an effort to minimize water loss due to evaporation, better direct the water to the vines, and reduce weed growth in the difficult to control undervine area.

Evoquer la notion de durabilité pour la vigne, plante multimillénaire, et le vin, tous deux intimement liés aux origines de notre civilisation, peut paraître un non-sens.

Nitrogen fertilization is an important practice to guarantee vineyards sustainability and performance over years, while ensuring berry quality. However, achieving a precise nitrogen fertilization to meet specific objectives of production is difficult. There is a lack of knowledge on the impact of nitrogen fertilizers (soil/foliar; organic/mineral) and different levels of fertilization on the interactions between carbon and nitrogen cycles within the vine. Crop models may be useful in that purpose because they can provide new insights of the effects of fertilization in carbon and nitrogen storage. The objective of this study is to build a model to simulate grapevine carbon and nitrogen content in vines to evaluate the impact of different fertilization strategies in vine growth and yield.

Malolactic fermentation (MLF) is a secondary step in the vinification process and it follows alcoholic fermentation (AF) which is predominantly carried out by Saccharomyces cerevisiae. These two processes result in the degradation of metabolites to produce secondary metabolites which also contribute to the final wine flavour and quality. AF results in the production of ethanol and carbon dioxide from sugars and MLF stems from the degradation of L-malic acid (a dicarboxylic acid) to L-lactic acid (a monocarboxylic acid). The latter process results in a smoother texture as the acidity of the wine is reduced by the process, it also adds to the flavour complexity of the wine.

Issues that can arise during the alcoholic fermentation are frequently attributed to imbalances or deficiencies in the nutrient composition of the fermentation medium.