Andras Forgacs started getting calls from the last group of people he imagined would be interested in his company--fashionistas.

It was 2011, and he had just stepped away from his leadership role at Organovo, a startup that 3-D-printed skin tissue for medical use. It turned out, the fashion executives told him, leather is a gnarly industry. Livestock create one-fifth of the world's greenhouse gases, and an estimated one-third of leather hides produced end up in landfills. The demand for leather goods was booming, yet there were shortage issues, and synthetic leather alternatives performed poorly.