Would you eat a cookie made out of plastic? If humankind ever runs out of farmland, our next meal might literally be the trash we threw away. Researchers at Southern Illinois University Carbondale have engineered specialized yeast that breaks down plastic waste and crop scraps into edible proteins, fats and flavorings. Once processed, this nutrient blend is fed directly into a 3D printer to produce customizable, completely edible cookies. Nothing goes to waste.