Human waste management is one of the issues facing astronauts who will be sent on long-duration missions in space, but researchers from Clemson University reveal that they may have a solution for it with the help of engineered yeast.
According to the scientists who presented their research at the 254th National Meeting & Exposition of the American Chemical Society, engineered strains of the yeast Yarrowia lipolytica have the capacity to turn untreated human urine into plastic polymers that can be used for 3D printing.
The technology is helpful for space exploration since astronauts will not be able to bring many spare materials for space exploration, especially for missions beyond the Earth's moon, though it is mostly because of the added fuel cost for the rocket.
"If astronauts are going to make journeys that span several years, we'll need to find a way to reuse and recycle everything they bring with them. Atom economy will become really important," Mark A. Blenner said.
The researchers focused on the idea of recycling and repurposing waste molecules so astronauts would only need urine, breath, and yeast to turn biological waste into something more useful for exploration.
How The Engineered Yeast Works
Yarrowia lipolytica typically needs nitrogen and carbon to grow, so the researchers looked for possible sources of those during long space flights and found the answer in the astronauts themselves.
According to the study, astronauts can use nitrogen from untreated urine and carbon from their exhaled breath to jumpstart the yeast's growth. However, the yeast needs a helping hand to separate the carbon from CO2, and that comes in the form of the blue-green algae called cyanobacteria.
With all the ingredients in place, the yeast will churn out monomers and link them together to create polyester polymers. These polymers can then be used for 3D printing the tools or parts the astronauts would need.
However, it is not just plastic polymers the human waste and yeast combination can produce because it can also produce Omega-3 fatty acids, which are actually important for heart and metabolic health. Since a different study using the same yeast already makes Omega-3 supplements for aquaculture, the researchers are looking into doing the same thing for human nutrition.
Watch the video below to understand how the yeast works.
There's also the fact that ISS astronauts are already repurposing their waste for consumption so a health supplement is just additional nutrition.
"We currently drink our processed pee and sweat on the ISS," STEAM educator and former NASA astronaut Leland Melvin revealed in an interview.
Ingesting omega-3 supplements from human pee doesn't seem too savory for people on Earth but astronauts with very limited resources in space can't really be picky.