And making heme is what they are proud of at impossible foods. https://impossiblefoods.com/heme

“Heme is what makes meat taste like meat. It’s an essential molecule found in every living plant and animal – most abundantly in animals – and something we’ve been eating and craving since the dawn of humanity. Here at Impossible Foods, our plant-based heme is made via fermentation of genetically engineered yeast, and safety-verified by America’s top food-safety experts and peer-reviewed academic journals. Watch more below.”