“Commercial chemical fertilizers don’t contain organic carbon,” Brennan said, “but the carbon in the duckweed stays in the soil for multiple seasons, enriching the quality of the soil and contributing to the overall health of the soil ecosystem.”
To help with the original research, Brennan said she started collaborating with people who have expertise in plant science and soil microbiology. Now Brennan is also collaborating with experts in food science and science communication as her team looks to validate duckweed as a source of high-quality protein for meat and dairy animals, and eventually humans.
In addition to its uses as a food and fertilizer, duckweed is an exceptional candidate for biofuel.
“Duckweed changes its metabolism depending on the water quality in which it’s grown,” Brennan said. “If you grow it in very nutrient-rich waste, it synthesizes a lot of protein.”
However, if the nutrients to build proteins are in very low amounts, the plant preferentially sequesters starch, which can be easily converted into biofuels such as ethanol and methane, and other commodity chemicals that are eco-friendly.
“For a biofuel to be cost-competitive, you have to be able to use every single component of a crop,” said Brennan. “Even after we produce biofuels, there is a small amount of residual waste from duckweed left over, and that can be used as fertilizer or animal fodder.”
This little plant may even be heading to space. Because the plant takes very little room to grow (just a couple of inches of water) and is plentiful (doubling every couple days), duckweed is ideal for space travel.
“The plant could be used to purify the astronauts’ air and wastewater,” Brennan said. “Or it could be consumed or used as a fertilizer to help grow vegetables. Duckweed has already been tested in the Spacelab, and future experiments to test its ability to survive extended spaceflight missions are underway.”