Something In The Air

Only a fraction of the world’s yeast species have been discovered. The remainder could hold the keys to ending disease, climate change, and bad beer.

- Sarah Musgrave

THE OAK savannah of Ontario’s Pinery Provincial Park is humid, sunny, and still. The only visible movement comes from microbiologist Marc-André Lachance, who is sniffing a tree trunk. With his beard, shades, and Tilley hat, Lachance looks like a cross between a birder and a member of ZZ Top. His nose has picked up a distinctive tarry odour, like carbolic soap. “Aha, flux city!” he declares, then carefully scrapes a sterilized metal spatula against a slime flux — a cluster of dark sap from a wound to the bark — to get the invisible beings he is after. Lachance is hunting wild yeasts, and he’s one of best hunters in the world.

Lachance is sometimes referred to as “the OG of yeasts” by a younger generation of researchers, though his only vanity seems to be his licence plates: YeaSTS, emphasis on the plural. He has spent the past forty years stalking these single-celled organisms — which are members of the fungi kingdom — from Australia to Brazil, Malaysia to Belize, researching how insects and plants interact to foster yeast habitats. Where vacationers bring skis or snorkels, Lachance carries sampling vessels, bug dope, soft tweezers for insects, hard ones for cactus spines, and the strongest drugstore reading glasses available (“like a microscope around your neck,” he explains). Modern yeast hunters also travel with permits; in an era of bioprospecting, legal conflicts over microbial ownership are rendering visible the value of the invisible, and yeasts have become big business.