Humble houseplants have long been known to bring benefits that go way beyond brightening a room, and now researchers have given their powers an extra boost, turning a popular species of climber into an air purifier.
A team of scientists at the University of Washington in the United States made the golden pothos (Epipremnum aureum) remove toxic gases from the air by inserting a rabbit gene called CYP2E1 into its DNA.
The air breathed in homes usually contains more harmful compounds than office or school air, according to the study.
“This is the first houseplant that has been transformed to break down toxic compounds in the home,” study author Stuart Strand told CNN via telephone.
This gene, which is present in all mammals, makes an enzyme called cytochrome P450 2E1 that breaks down a number of volatile organic compounds (VOCs), many of which are toxic. The enzyme also metabolizes alcohol in the human liver.
But the team focused in on its ability to break down the harmful compounds benzene and chloroform, which have been linked with cancer, according to the American Cancer Society and the US Environmental Protection Agency.
These compounds are produced by many sources in the home, such as showering, cooking, smoking and even furniture.
To test the plants’ powers of purification, the team placed unaltered as well as altered plants in glass tubes containing either chloroform or benzene gas and left them for 11 days before measuring the concentration of gas in each of the tubes.
Unaltered pothos plants did break down chloroform and benzene to clean the air, but the researchers found that the modified plant did so far more efficiently — making it more useful as a potential filter in the home.
The plants destroy these compounds rather than store them, explained Strand, turning chloroform into chloride ions and carbon dioxide, which it then uses during photosynthesis. They also convert benzene into phenol, which is used to build plant cell walls.
The researchers are now working on adding another protein to the plants that would remove formaldehyde from the air, according to the study, published in the journal Environmental Science & Technology.
Formaldehyde — found in cigarette smoke — is another harmful compound and known human carcinogen, according to the International Agency for Research on Cancer (IARC).
Genetically modified pothos could reduce cancer rates, said Strand, particularly among people who traditionally spend a lot of time at home, such as children.
Pawel Misztal, an atmospheric chemist/physicist at the UK’s Centre for Ecology & Hydrology, told CNN that the study is interesting for its focus on indoor pollutants, but there are better ways to reduce exposure.
Misztal said he is skeptical that plants can solve the air quality issue, adding that “ventilating the house by opening windows or active ventilation systems seems by far the most effective means to reduce the concentrations of VOC pollutants.”
Liz Rylott, a plant biotechnologist at the University of York, in the UK, told CNN via telephone that the study is a great proof of concept.
“The potential is extraordinary,” said Rylott. “Reducing your exposure to these compounds can only be a good thing.”
“It really is a bit of a game-changer,” she added.
However, she was also keen to emphasize that there are other important ways to reduce our exposure to harmful compounds, including the age-old advice of eating green vegetables containing antioxidants and getting out of the house for some fresh air.
Strand has received regulatory approval to sell the plants in Canada and is currently looking for a commercial partner. In the US, the team is waiting on approval from the Department of Agriculture to sell the plants.
The research is one of a growing number of studies exploring ways in which we can modify plants to perform different tasks.
In July, scientists at the University of Tennessee proposed genetically engineering plants to act as biosensors that warn us of the presence of dangerous compounds such as mold.
And engineers at the Massachusetts Institute of Technology (MIT) have been tinkering with the actual composition of plants to get them to perform diverse, even outlandish, functions. Projects include printing sensors onto plants’ leaves to show when they’re short of water; one that can record and transmit 3D images of its surroundings; and even a plant that can detect chemicals used in explosives in groundwater.