But what if we could do something else—anything else—with all these boxes? Like fuel a car? Thanks to Sun-Mi Lee, a research scientist at the Clean Energy Research Center of the Korea Institute of Science and Technology, maybe we can. Her team has cultivated its own microorganism to transform used cardboard boxes into a substance that can be easily refined into biofuel.
As of today, the U.S. makes most of its biofuel from fermenting corn into ethanol. Ethanol is often cut into more typical gasolines, and it represents about 10% of all gas sold in the U.S. But creating ethanol is not the most efficient of processes, and it taps a food source for energy with real consequence. Ethanol production has actually driven up food prices, which is problematic in a world where food production will increasingly be a concern.
Another biofuel alternative is biodiesel, which we often produce from used food oils, like soybean oil or corn oil. It’s more energy-efficient than ethanol and burns cleaner. And like ethanol, most biodiesel is cut into existing fuels. Lee’s efforts are around biodiesel, but created from a novel source.
In the lab, Lee’s team bred its own yeast that could chew on cardboard to make the key component of biodiesel. How does it work? There are actually sugars trapped inside cardboard boxes—specifically glucose and xylose—and the yeast is able to transform those sugars into combustible fats used in biodiesel. Researchers have tried this approach before, but microorganisms were unable to process the xylose. Since about one-third of the sugar in cardboard is xylose, that left a lot of untapped energy.
Lee’s team cultivated yeast down a certain evolutionary path to create a microorganism that could turn all of the available sugars in cardboard into fats. And the yeast doesn’t just munch cardboard: It can process any common paper, as well as waste plant matter from farming and logging. In this sense, Lee’s approach to producing biodiesel is especially notable compared to how we currently make ethanol. Instead of using food to create energy, it uses waste.
Of course, this doesn’t mean we’ll be shoving out Amazon boxes into fuel tanks any time soon. These scientific breakthroughs have to be proven out to be cost-efficient at scale, then make their way into production. But having more good ways to turn our refuse into fuel is necessary for the future of our planet. And . . . okay . . . it would alleviate some of the guilt I have from this tower of Amazon boxes in my basement.