There are plenty of tough problems NASA has to work out before it can send astronauts on long-term manned missions to planets like Mars, but one of the biggest questions is sustenance. When we have sent robots to Mars, the trip has taken around eight months, but it required no food. If we were to send humans out into space for months at a time, they would need to either pack or grow enough food to keep them from starving for the entire duration of their mission. One answer may lie in our toilets, as The Independent reports.

In a study in the journal Life Sciences in Space Research, Penn State University astrobiologists report that with a little microbial magic, they can potentially turn wastewater into food. Using the methane produced during an anaerobic waste treatment process (a oxygen-free technique already used to treat Earthly sewage), they were able to culture three bacterial species, two of which—Methylococcus capsulatus and Thermus aquaticus—yield "protein- and lipid-rich biomass that can be directly consumed," according to the study. Yum.

In The Independent, Penn State professor Christopher House describes the resulting "microbial goo" as being kind of like Vegemite or Marmite. In theory, you could either eat it by itself—poop toast, anyone?—or use it as a high-protein supplement to feed fish, insects, or other live food sources.

Plenty of testing remains to be done before this type of microbial mixture could be made into human food at all, much less deployed on a spacecraft, where everything has to be perfectly engineered to balance astronauts' needs with space and weight considerations to stay fuel-efficient. But in Europe, the microbe is already approved to feed fish, pigs, and other farmed animals, so it wouldn’t be a stretch to think it could feed animals on a space ship. Whether astronauts will be eating it for months on end will have to be seen.

[h/t The Independent]