In winemaking, terroir factors—including climate, temperature, water availability, and soil characteristics—directly influence grape development and composition. Once harvested, the grapes undergo wine fermentation, a crucial process that transforms natural fruit sugars into alcohol, defining the wine's final quality, unique aromas, and characteristics.
Behind this process lies the microscopic world of wine yeast. To remain active during fermentation, these vital microorganisms require specific nutrients for metabolic growth, including essential carbon sources, vitamins, minerals, and nitrogen.
Nitrogen deficiency in grape must is a historic challenge for wine fermentation, as low nitrogen levels decrease yeast activity and cause slow or stuck fermentation. To prevent production losses, the wine industry has standardized the exogenous supplementation of nitrogen to maintain a stable, efficient production process.
To address this industry challenge, Usach researcher Dr. Eduardo Kessi is leading a Fondecyt Regular 2026 project at CECTA to study the genetic and molecular mechanisms of wine yeast. By analyzing how specific strains adapt to low nitrogen availability, this research aims to optimize wine fermentation efficiency and secure stable wine production when nutrients are scarce.
"This is a historic challenge for the global wine industry, which is why supplementing with exogenous nitrogen during fermentation has become standard practice," explains Usach researcher Dr. Eduardo Kessi. "Nitrogen in grape must is vital for wine yeast; when levels are insufficient, fermentation can stall and cause massive production losses. That is exactly why our research focuses on identifying specific yeast strains capable of efficient wine fermentation under low nitrogen availability.”
The research focuses specifically on the TORC1 signaling pathway (Target of Rapamycin Complex 1), which coordinates wine yeast growth based on nutrient availability. In simple terms, the TORC1 pathway functions as a biological sensor, allowing yeast cells to detect whether environmental conditions are optimal for cell division and active wine fermentation.
“The TORC1 pathway coordinates cell growth in response to available nitrogen sources, making it a critical mechanism across all eukaryotic organisms," notes Dr. Eduardo Kessi. "In humans, the TOR pathway is linked to cancer development, while in yeast biology, it dictates how the organism responds to nutrients. This raises a fundamental question: how does nitrogen availability activate this pathway? If wine yeast detects insufficient nutrients, it stops growing, and wine fermentation ceases completely.”
To advance this research, the project will analyze wild and domesticated yeast strains from diverse ecological niches to identify genetic variants linked to TORC1 pathway activation. Researchers will then use advanced gene-editing techniques to introduce these target variants into commercial wine yeast, evaluating whether the modified strains can achieve highly efficient wine fermentation under low-nitrogen conditions.
“Our goal is to modify these genes in wine yeast strains and evaluate if they perform better during fermentation under low-nitrogen conditions," adds Dr. Kessi. "To achieve this, we will use CRISPR-Cas gene-editing tools, which allow us to make precise modifications to the yeast genome without introducing foreign DNA. It is a highly accurate method to identify exactly which genetic variants drive superior wine fermentation capacity.”
Beyond its impact on winemaking, this project drives the development of sustainable biotechnology tools to optimize industrial fermentation. By engineering resilient yeast strains, this research aims to eliminate the need for artificial nitrogen supplementation in grape must, creating a more cost-effective, efficient, and environmentally sustainable wine production process.
“Wine production is one of Chile’s most vital economic industries, making the optimization of wine fermentation always highly relevant," concludes Dr. Kessi. "However, this basic science research is crucial even beyond immediate practical applications. For instance, while we are currently studying the TORC1 pathway in yeast biology, tomorrow that exact genetic knowledge could drive medical breakthroughs in the search for cancer treatments.”
Finally, Dr. Kessi emphasized that funding basic science research is essential for driving Chile's scientific and technological development. He noted that these institutional grants are critical for fostering innovation in biotechnology, building national research infrastructure, and positioning the country as a leader in global scientific discovery.
“This is exactly why public funding for basic science research—such as Fondecyt projects—is so critical for the country's future," concludes Dr. Eduardo Kessi. "Even though basic research may lack an immediate commercial application, it forms the vital foundation for generating the advanced knowledge that will drive future technological developments we cannot even imagine today.”