Molly Morse is the CEO and co-founder of Mango Materials, a Bay Area company that turns methane into a biodegradable plastic alternative. Its material is grown by bacteria that eat methane and store a natural polymer, PHA, in their cell walls, which Mango harvests into pellets that behave like conventional plastic but break down naturally at the end of life.

In this conversation with Daniel Epstein, Molly explains the science in plain language: why methane, a greenhouse gas 20 to 80 times more potent than carbon dioxide, makes the material carbon-negative going in, and why PHA breaks down in the natural environment and even in the human body, unlike the petrochemical microplastics now found in our blood. She traces the company from its origins in a Stanford PhD to products shipping today, from Natura soap dishes to Stella McCartney sunglasses, and is candid about the one barrier that remains: the scale needed to reach price parity with petroleum plastic.

The conversation also goes personal. Molly talks about descending from a family of inventors, with a distant tie to Samuel Morse and a great-grandfather who commercialized the bicycle chain; what it has meant to build a hard-science company as a woman and a mother in a field that still treats both as risks; why we can't recycle our way out of plastic pollution; and the humor and clarity that keep her going.

Molly joined the Unreasonable Fellowship in 2022 through the Unreasonable Impact program, run in partnership with Barclays.

(00:00) Introduction

(02:54) What Mango Materials Is

(03:32) Feeding Methane to Bacteria: How PHA Is Made

(06:31) Why Methane, Not CO2, and Why It's Carbon-Negative

(08:12) From Oakland to a College "Garbage" Class

(09:13) The Stanford Detour: A Master's Becomes a PhD

(10:01) The Breakthrough: Making PHA From Methane

(11:11) "How Hard Could It Be?": Starting Mango

(12:02) First Funding and Raising $55 Million

(14:03) What Mango Ships: Natura, Allbirds, Stella McCartney

(15:02) How PHA Performs While You Use It

(16:22) The Catch: Economics and the Need for Scale

(18:24) What a $500 Million Offtake Agreement Would Unlock

(20:00) Why the Big Buyers Haven't Committed Yet

(23:21) The Truth About Recycling

(26:31) How Long It Takes to Break Down, and Microplastics in the Body

(29:59) A Family of Inventors: Morse Code and the Bicycle Chain

(32:44) Swimming Against the Current: Women in Deep Tech

(36:48) Her Deep Why: "Born This Way"

(38:32) The Engineer's Mind, the Hypomanic Edge, and Handling Doubt

(43:35) Being a Mom and a CEO

(49:35) The Vision: Methane Everywhere, and On to the Galaxy

(52:47) How to Get Involved, and Why "Mango"

(55:27) Closing Reflections