December 19, 2018
Whether you're already using houseplants to clean the air in your home, or if you call upon electronic air purifiers, lend us your ear: Researchers at the University of Washington have genetically modified a common houseplant — pothos ivy — to remove chloroform and benzene from the air around it.
Apparently, certain hazardous compounds are too small to be trapped in standard purifying filters. Molecules like chloroform, which is present in small amounts in chlorinated water, or benzene, which is a component of gasoline, build up in our homes when we shower or boil water, or when we store cars or lawn mowers in attached garages.
Why does that matter? Because exposure of benzene and chloroform have been linked to cancer, Science Daily reports.
Published in Environmental Science and Technology, researchers used genetic science to create a modified plant that produces a protein, called 2E1, that transforms these harmful compounds into molecules that the plants can then use to support their own growth. Further, the protein is able to break down benzene and chloroform into harmless byproducts, much like the liver does in the human body.
As an aside, 2E1 is actually present in all mammals, including humans.
"We decided we should have this reaction occur outside of the body in a plant, an example of the 'green liver' concept," senior author Stuart Strand, who is a research professor in the University of Washington's civil and environmental engineering department said.
The researchers made a synthetic version of the gene that serves as instructions for making the rabbit form of 2E1. Then they introduced it into pothos ivy so that each cell in the plant expressed the protein. "Without proteins to break down these molecules, we'd have to use high-energy processes to do it. It's so much simpler and more sustainable to put these proteins all together in a houseplant," Strand explains.
They then tested how well their modified plants could remove the pollutants from air compared to normal pothos ivy. They put both types of plants in glass tubes and then added either benzene or chloroform gas into each tube. Over 11 days, the team tracked how the concentration of each pollutant changed in each tube.
For the unmodified plants, the concentration of either compound didn't change over time. But for the modified plants, the concentration of chloroform dropped by 82 percent after three days, and was nearly undetectable by day six. The concentration of benzene also decreased in the modified plants, but more slowly: By the eighth day, benzene concentration dropped by about 75 percent.
It's worth noting that in order to detect these changes in pollutant levels, the researchers used much higher pollutant concentrations than are typically found in homes. Researchers suspect that home levels would drop at the same rate, if not more quickly.
To reap the air-purifying benefits, plants in the home need to be near something to move air past their leaves, like a fan, Strand said. "If you had a plant growing in the corner of a room, it will have some effect in that room, but without air flow, it will take a long time for a molecule on the other end of the house to reach the plant," Strand explains.
The team is currently working to increase the plants' capabilities by adding a protein that can break down another hazardous molecule found in home air: formaldehyde, which is present in things such as wood products like laminate flooring and cabinets.
Unfortunately, these super-plants are not commercially available yet. However, you can check out this list of the best air-cleaning house plants to get the ball rolling.