To a better understanding of the stuck fermentation during spontaneous fermentation due to microbial interactions and the chemical composition of the must

• Applicant: Professor Dr. Helmut König
• Co-Applicants: Dr. Danièle Evers; Professor Dr. Lucien Hoffmann
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2011 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 188542383

To compete with high quality wines from abroad, the wines from Germany and Luxembourg need to develop a more characteristic and superior sensory profile. During spontaneous fermentation, applied by wine makers of the upper quality segment, the activity of the wine yeast Saccharomyces cerevisiae can slow down or even decline to zero. Some reasons for this unsuccessful fermentation are known (e.g. lack of nutrients, unfavourable temperature or pH as well as a low glucose/fructose ratio), but the problem can often not be solved by the application of classical measures (e.g. temperature adjustment, the addition of nutrients or sparkling wine yeasts). In addition, wine makers of the upper quality segment avoid these procedures, since they could change the characteristic sensory profiles of the individual wines. We would like to investigate the so far overlooked problems during spontaneous fermentation, applied for the production of high quality wines, which may be caused by interactions between the diverse species of the microbiota among themselves and influenced by certain chemical compounds produced during the fermentation process. Therefore, we will focus on the determination of the microbial diversity and succession at different stages of the fermentation process, their inhibitory and stimulating cell interactions, interactions of cells with selected must constituents and the impact on the physiological status of the cells (proteomics) during the fermentation period. The aim is to avoid stuck fermentations and to produce high quality wines by spontaneous fermentations.

• DFG Programme: Research Grants
• International Connection: Luxembourg
• Partner Organisation: Fonds National de la Recherche
• Participating Person: Dr. Annemieke Ultee