Expanding the genetic engineering toolbox and biosensing capabilities of Saccharomyces cerevisiae and Debaryomyces hansenii

Over the past decades, bioengineering and synthetic biology have seen remarkable progress. Much of this progress relies on genetic engineering tools developed for working with different microorganisms. Among these, the yeast Saccharomyces cerevisiae, commonly used in baking and brewing, has emerged as a powerful tool beyond its traditional roles. One important use of S. cerevisiae is to create biosensors—tiny biological devices that can detect specific molecules inside or outside cells. Biosensors can be used to study human diseases and medicines and sense chemicals in the environment.

Some of these biosensors use structures known as receptors on the outside of the yeast cell. In this thesis, we engineered yeast to have human receptors to create biosensors so we can study how different drugs, aromas, and chemicals affect human receptors. We can also express receptors from other organisms, such as insects, to understand which odours are attractive or repulsive to insects, which could lead to pesticide-free pest control.

There is also increasing interest in using less common yeasts like Debaryomyces hansenii, which can grow in salt water. This yeast is already used in the food industry to produce certain cheeses but could be used to produce various molecules (such as medicines) in saltwater fermentations. Since biotechnological fermentation processes typically use a lot of fresh water, using saltwater could greatly reduce the need for freshwater, helping to conserve this valuable resource.

This thesis explores these innovations by expanding the genetic engineering tools available for S. cerevisiae and D. hansenii. It involves designing new yeast-based biosensors, improving methods for engineering yeast, and using robots to make yeast engineering faster and more reliable.