Genetically Modified Houseplant Can Clean Indoor Air

A team of scientists at the University of Washington has genetically modified a common houseplant, the pothos ivy (Epipremnum aureum), to efficiently remove two toxins — chloroform and benzene — from the air around it. The transgenic plant expresses a protein that transforms toxins into molecules that the plant can then use to support its own growth.

Genetically modified pothos ivy (Epipremnum aureum). Image credit: Mark Stone / University of Washington.

Indoor air often contains volatile organic compounds such as formaldehyde, benzene and chloroform.

These toxins come from many sources, including cooking, showering, furniture and smoking.

House plants can remove some toxins from the air, but they aren’t very efficient: a homeowner would need more than 20 plants to remove formaldehyde from a typical room.

“People haven’t really been talking about these hazardous organic compounds in homes, and I think that’s because we couldn’t do anything about them,” said Professor Stuart Strand, from the Department of Civil and Environmental Engineering at the University of Washington.

“Now we’ve engineered houseplants to remove these pollutants for us.”

Professor Strand and co-authors wondered if introducing a mammalian gene called CYP2E1 to the pothos ivy would boost the plant’s detoxifying potential.

This gene encodes cytochrome P450 2E1 (2E1 for short), a protein that breaks down a wide range of volatile organic compounds.

In our bodies, 2E1 turns benzene into a chemical called phenol and chloroform into carbon dioxide and chloride ions. But 2E1 is located in our livers and is turned on when we drink alcohol. So it’s not available to help us process pollutants in our air.

“We decided we should have this reaction occur outside of the body in a plant, an example of the ‘green liver’ concept,” Professor Strand said.

“And 2E1 can be beneficial for the plant, too. Plants use carbon dioxide and chloride ions to make their food, and they use phenol to help make components of their cell walls.”

The team introduced rabbit CYP2E1 to the ivy’s genome and injected benzene or chloroform gas into closed vials that contained growing plants.

After three days, the concentrations of these compounds in the vials had dropped dramatically, and by eight days, chloroform was barely detectable.

In contrast, the compounds’ concentrations in vials containing unmodified ivy or no plants did not change.

“A hypothetical biofilter made of the genetically modified plants would deliver clean air at rates comparable to commercial home particulate filters,” the study authors said.

The results appear in the journal Environmental Science Technology.

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Long Zhang et al. Greatly Enhanced Removal of Volatile Organic Carcinogens by a Genetically Modified Houseplant, Pothos Ivy (Epipremnum aureum) Expressing the Mammalian Cytochrome P450 2e1 Gene. Environ. Sci. Technol, published online December 19, 2018; doi: 10.1021/acs.est.8b04811