Leather doesn't have to come from animals

We're making new textiles from yeast.

making leather out of yeast on petri dish
Functional fungi.illustration by Rafael Alvarez

From Suzanne Lee, Chief Creative Officer of Modern Meadow

Leather is difficult to mimic without animals, which use up lots of land and water. Instead, we engineer yeast cells that produce collagen proteins as they ferment. We purify what comes out and turn it into a material that tries to imitate a hide.

Our team helps companies that want to make leatherlike vegan products. But communication can be difficult. Designers speak about materials based on their instincts about texture and sense of touch—two very subjective things. But scientists want to know about the mechanics, such as tensile strength, which is the measure of how far a substance can bend without breaking. So a brand would come back to us and say, “It needs to feel richer,” and you’d get a room of blank faces from the scientists. They’d ask, “What is richness?” We sat with samples for months on end, just kind of piling them up, feeling them, and asking: “What does it feel like? Is it more dry? Waxy? Oily? Powdery? What makes something ‘rich’?”

To answer these questions, the design team developed a system to grade substances on a scale from zero to 10 for each subjective factor, such as richness. It’s been surprisingly accurate, and has allowed everyone to work together.

Getting something durable, high-​­performing, good-​­looking, and comfortable—and all for the right price—is still challenging. But there's a lot of interest in what we're doing. We're pushing people to think differently. And, as we ramp up production, we estimate we'll be using far fewer resources than traditional leather-production methods.

This article was originally published in the Summer 2019 Make It Last issue of Popular Science.