Capturing carbon with cheese? No whey!

What if the leftovers behind your queso dip and tofu bowl could help clean carbon dioxide from the air?

That’s the idea behind a new study from researchers at ETH Zurich. They have found a way to turn food industry waste into tiny carbon-capturing beads. This solution, they say, is a more efficient and lower-energy way to pull CO2 directly from the atmosphere. 

The process focuses on two often-overlooked leftovers: whey from cheese production and protein-rich byproducts from tofu manufacturing. While some of that material gets reused, much of it gets thrown out. 

Instead of tossing it, researchers extract proteins from those leftovers and transform them into thread-like structures called amyloid fibrils. Those fibrils are then loaded with potassium hydroxide and shaped into porous beads, essentially turning food scraps into what researchers describe as a kind of carbon sponge. 

And when it comes to carbon, these beads don’t just nibble, they feast.

When exposed to the atmosphere, the potassium hydroxide reacts with carbon dioxide to form hydrogen carbonate, effectively removing CO2 from the atmosphere. In laboratory tests, researchers found that just 1 gram of the material captured 97 milligrams of carbon dioxide. That’s 10% to 50% more efficient than conventional direct air capture methods, according to the study. 

In carbon capture, those numbers are anything but bite-sized.

Conventional methods of carbon capture, called direct air capture (DAC), has become an important piece of long-term climate strategies because it removes carbon already in the atmosphere. Most of these systems require a lot of heat and energy to release the captured CO2 for storage or reuse.

This new cheese and tofu method is different.

Instead of cranking up the heat, researchers say the protein beads can release the trapped carbon at room temperature by being sprayed with a mild acid and base for about 10 minutes. That lower-energy process could make the system cheaper and easier to scale, giving traditional carbon capture technologies some food for thought. 

The beads also showed staying power. In lab testing, they maintained their performance through 30 cycles of capturing and releasing carbon without major efficiency loss. Eventually, after thousands of cycles, researchers say the material could still have a second life as fertilizer or even biofuel.

That means this climate solution may not just help cut carbon, it could keep waste out of landfills too.

For now, the technology has only been tested in small, controlled lab settings. But researchers say they’re confident it can scale up.

Just think, the next tool in the fight against climate change may not be cooked up in a factory, but in the leftovers from your lunch.