The ability of wine yeasts fermenting by the addition of exogenous biotin

According to the Food and Agriculture Organisation (FAO), 75.866 km2 of the world is dedicated to grape cultivation. About 71.0% of the world’s grape production is destined for winemaking, 27.0% for consumption as fresh fruit and 2.0% as raisin. Grape production is mainly hindered by fungal infections, that can develop both in field and post-harvest.

Microorganisms have been widely used in oenology since prehistoric times. Their metabolism significantly impacts many wine properties and is particularly essential for the production of flavor compounds, thereby affecting perceived wine quality.

In contrast to fruit and grape berry ripening, the biological processes causing ripening disorders are often much less understood, although shriveling disorders of fruits are manifold and contribute to yield losses and reduced fruit quality worldwide. Shrinking berries are a common feature for all shriveling disorders in grapevine although their timing of appearance during the berry ripening process and their underlying induction processes distinct them from each other. The sugar accumulation disorder Berry Shrivel (BS) is characterized by a suppression of sugar accumulation short after veraison resulting in berries low in sugar content and anthocyanins in berry skins, while the organic acid content is similar. Recent studies analyzed the biochemical, morphological and molecular processes affected in BS berries and linked early changes to the period of ripening onset [1,2].

In Castilla-La Mancha as other winegrowing regions, vineyards suffer the effects of the global climate warming. Severe spring and summer droughts are increasingly frequent, which concur with the phenological stages most susceptible to water and temperature stress. Under these conditions, irrigation use is required in order to ensure the vineyard growing sustainability. However water resources are increasingly limited, for this reason is required to choose cultivars displaying high water use efficiency.

Oxygen plays a key role in the evolution of wine chemistry, within the non-volatile matrix. Polyphenol composition and structure, as well as the process of tannin polymerisation are directly impacted by oxidation, and this can occur during both fermentation and ageing.