In nature, enzymes are the catalysts that make much of biology work. They jumpstart chemical reactions that either wouldn’t happen, or would happen super slowly. They break down food, build other molecules, extract energy, and more. What if we could harness evolution to engineer designer enzymes that do other specific jobs that benefit us?  Putting that idea into practice changed the game for chemistry, and earned Frances Arnold the Nobel Prize prize in 2018. She called it “directed evolution.” Today, thousands of labs use her methods to coax enzymes into doing things no one ever thought of. She joined Host Flora Lichtman in March 2026 to talk about where she sees this approach going in the future, and the personal evolution that brought her into science. Guest:  Dr. Frances Arnold is the Linus Pauling Professor of Chemical Engineering, Bioengineering and Biochemistry at the California Institute of Technology in Pasadena, California. Other episodes you may enjoy: • Enzymes Are Taking On Our Plastic Problem (https://www.sciencefriday.com/segments/new-plastic-eating-enzyme?utm_source=wnyc&utm_medium=podcast&utm_campaign=scifri?) • Even Nobel Prize Winners Deal With Imposter Syndrome (https://www.sciencefriday.com/segments/ardem-patapoutian-biology-nobel?utm_source=wnyc&utm_medium=podcast&utm_campaign=scifri?) The transcript for this episode is available at sciencefriday.com (https://www.sciencefriday.com/segments/frances-arnold-enzyme-engineer-chemistry/?utm_source=wnyc&utm_medium=podcast&utm_campaign=scifri) . Subscribe to this podcast. (https://pod.link/73329284) Follow our show on Instagram (https://www.instagram.com/scifri/) , TikTok (https://www.tiktok.com/@scifri) , Facebook (https://www.facebook.com/scifri) , and Bluesky (https://bsky.app/profile/scifri.bsky.social) @scifri and sign up for our newsletters (https://www.sciencefriday.com/newsletters/?utm_source=wnyc&utm_medium=podcast&utm_campaign=scifri) . Got a science question that’s keeping you up at night? Call us: 877-472-4374 (about:invalid#zCSafez) Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com (https://pcm.adswizz.com) for information about our collection and use of personal data for advertising.