Back in our research days, we used to harvest leghemoglobin directly from the roots of soy plants. But we soon realized that in order to make enough plant-based heme to feed the world (and to avoid digging up soy plants to harvest the root nodules, which would promote erosion and release carbon stored in the soil) we would need to make it using fermentation.
The heme in the Impossible Burger is made using a yeast genetically engineered with the gene for soy leghemoglobin. First, we grow yeast via fermentation. Then, we isolate the soy leghemoglobin (containing heme) from the yeast and add it to the Impossible Burger, where it combines with other micronutrients to create delicious, meaty flavor. This process allows us to make heme at scale with the lowest achievable environmental impact.
Learn more about how we make heme and get a peek behind the scenes in the video below.