Blenner's work focuses on taking biological waste like urine and even exhaled air and putting it to good use. The research team is using the waste to fuel a certain type of yeast -- Y. lipolytica -- that requires nitrogen and carbon to grow. And those yeast strains can produce useful chemicals like omega-3 fatty acids and monomers that can be linked to create polymers. Those polymers could in theory then be 3D printed into plastic parts. Overall, the work shows that human waste can be used to create necessary products for spaceflight while minimizing what's stored on board. "Having a biological system that astronauts can awaken from a dormant state to start producing what they need, when they need it, is the motivation for our project," said Blenner.

Right now, the yeast can only generate small amounts of product, but the team is working to increase their output. And they're exploring how this method can be used on Earth as well. "We're learning that Y. lipolytica is quite a bit different than other yeast in their genetics and biochemical nature," Blenner said. "Every new organism has some amount of quirkiness that you have to focus on and understand better."