With the project "Development of a fed-batch method for the optimal propagation of Saccharomyces cerevisiae for the fermentation of grape must", the Federal Agency for Agriculture and Food is funding the development of a bioreactor for yeast propagation and propagation for wine production. The project is being carried out by the Chair of Bioprocess Engineering at the Rhineland-Palatinate Technical University in Kaiserslautern together with the Institute of Food Science and Biotechnology at the University of Hohenheim, the company Kerafol Keramische Folien GmbH & Co. KG and the Lauth & Sohn winery.
Alcoholic fermentation is by far the most important step in the production of wine. Yeasts, Saccharomyces cerevisiae, are required for this. Until the 1980s, fermentation was still mainly carried out spontaneously by yeasts brought from the vineyard or present in the cellar (equipment, barrels). A fundamental change began in the 1980s: Musts were pre-clarified for the first time and fermented at a controlled temperature to produce pure and fruity aromas. This required the use of pure yeasts, usually in the form of dry yeasts. For safe fermentation of the grape musts, these dry yeasts require suitable conditions in the first step for propagation to a sufficient number of cells with high vitality. These conditions are often not optimal for grape musts in terms of temperature, nutrient content, oxygen requirements, etc.. This can lead to fermentation stagnation and fermentation breakage with negative quality development of the wines produced.
The aim of the project is to develop a bioreactor and the associated sensor system in order to optimize yeast propagation during wine production and thus to counteract fermentation stagnation and quality deterioration. In addition to conventional probes, the reactor will also be equipped with metal oxide gas sensors and optical sensors. Once a demonstrator has been completed, its functionality and process technology will be extensively tested and optimized until a fully qualified system is ready for use in wine production.
