Research Western

Marc-André Lachance: Rising to the Occasion

Despite the important role yeast plays in our ecosystem, we are unlikely to think much about it unless we are baking, brewing beer or suffering from an infection.

In fact, more than 20 million tonnes of one particular species of yeast are produced for the food and beverage industry annually – making it the most-grown microbe in the world – but biology professor Marc-André Lachance is more interested in the roles other species of the microorganism play in nature.

As individual yeast cells are invisible to the naked eye, Lachance is left to search many of the world’s most bio-diverse regions for yeasts found foaming at the base of plants and in areas rich in sugar or decomposing matter.

Much of his work examines the relationship between yeasts, flowering plants and sap beetles, which are known throughout the world to lay eggs at the bottom of plants and, at the same time, inoculate flowers with the microorganism. As the yeast multiplies, it acts as a protein and vitamin-rich food source for the sap beetles as their eggs develop and hatch.

“Yeast growing on plants increases the nutritional value of compounds on which insects feed,” Lachance says, pointing out that insects require additional proteins unavailable in a diet consisting simply of nectar. “As yeasts grow, they become food.”

Research related to the flower beetle system regularly carries him from the United States to Central and South America. “We are also fortunate to have very good relationships with researchers in Brazil, where we can get access to one of the best pools of biodiversity on Earth,” Lachance says.

“By documenting these sorts of interaction, we can begin to paint a picture of the process of species formation and the underlying causes of the global distribution of yeast,” he adds. Lachance is also interested in recording the biodiversity and movement of microorganisms, which can help us better understand how epidemics spread.

The Distinguished Research Professor and Florence Bucke Research Prize winner has contributed to understandings of the varied temperatures at which yeasts grow, but he hopes to gain a stronger grasp on how widespread these variations are. These findings can help us better understand climate change.

Enter Western’s Biotron Experimental Climate Change Research Facility, which is ideally suited for such studies.

“A huge effect of how yeasts are distributed is temperature, and how they deal with heat and cold,” Lachance says. “It’s simple to find out at what temperature yeast grows, but with the Biotron, the microbiology unit allows us to tell the minimum and maximum temperature various yeasts will grow at really quickly.”

It is an area of research that has only risen in prominence in recent years. Since the first discovery of yeast 100 years ago, scientists have discovered 1,500 species, more than half of which have been found in the past 15. Lachance has mathematically calculated that there are likely more than 15,000 species around the world, which leaves a lot of room for further discovery.