Making yeast work smarter
Due to climate change, grapes are becoming increasingly sweet. That may sound positive, but in winemaking it means more sugar. And therefore, a higher alcohol content and less freshness in flavour. At the same time, demand for alcohol-free beers is on the rise. Battjes’ research shows how yeast cells make choices when converting sugar into energy. “This may sound rather abstract, but it has direct practical implications: brewers, winemakers and, for instance, producers of biofuels can use this knowledge to improve their processes. By making yeast work more smartly, they can produce the desired products more efficiently, which saves costs and is more sustainable,” Battjes explains.
The use of these yeast strains is also socially relevant. More efficient use of raw materials means less waste and a smaller ecological footprint. Moreover, it addresses current issues such as sustainability and energy efficiency. In this way, fundamental research into cell behaviour is directly translated into practical solutions that benefit both industry and the environment.
Two useful yeasts identified
The research shows that the yeast Lachancea thermotolerans could help prevent excessively high alcohol levels in wine, as it converts part of the sugars into lactic acid rather than alcohol. This makes the wine fresher and less heavy. Battjes discovered that the switch to producing lactic acid occurs when the yeast can no longer access nitrogen, an essential nutrient. The yeast Pichia kluyveri may contribute to the production of alcohol-free beers, as it produces hardly any alcohol under oxygen-rich conditions.
Smart choices
But why do some yeasts opt for respiration and others for fermentation, even when oxygen is available? This so-called Crabtree effect may seem inefficient, but it is linked to the way cells use their limited protein machinery. The research shows that the efficiency of the proteome, the cell’s total protein capacity, determines which strategy a yeast chooses. Yeasts make smart choices in their metabolism, depending on their limitations. Sometimes they choose a route that yields less energy but requires less space and less protein machinery. This provides a better understanding of how yeasts grow and how they can be used intelligently.
Insights into behaviour directly applicable
To study the behaviour of yeasts, laboratory experiments were conducted to examine how yeast cells convert sugar into energy and which factors limit their efficiency. By testing various conditions, such as nutrient availability and growth medium composition, and combining the results with computer simulations, it became clear how internal constraints influence growth. This approach provided both practical data and insights into biological processes, allowing for a better understanding of yeast behaviour and direct application in the food and biotechnology industries.