Researchers at the University of Washington have genetically modified a pothos ivy to remove chloroform and benzene from the air around it. The modified plants express a protein, called 2E1, that transforms these compounds into molecules that the plants can then use to support their own growth. The team published its findings Dec. 19 in Environmental Science & Technology. Both benzene and chloroform exposure have been linked to cancer.

“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," says senior author Stuart Strand, who is a research professor in the UW's civil and environmental engineering department. "Now we've engineered houseplants to remove these pollutants for us."

The team used a protein called cytochrome P450 2E1, or 2E1 for short, which is present in all mammals, including humans. 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. 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," Strand says. "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 researchers also tested how well the modified plants could remove the pollutants from air compared to normal pothos ivy.

For the unmodified plants, the concentration of either gas didn't change over time. But for the modified plants, the concentration of chloroform dropped by 82 percent after three days, and it was almost undetectable by day six. The concentration of benzene also decreased in the modified plant vials, but more slowly. By day eight, the benzene concentration had dropped by about 75 percent. To detect these changes in pollutant levels, the researchers used much higher pollutant concentrations than are typically found in homes. But the team expects that the home levels would drop similarly, if not faster, over the same time frame.

For the best results, plants in the home would also need to be inside an enclosure with something to move air past their leaves, like a fan, Strand says.

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 some wood products, such as laminate flooring and cabinets, and tobacco smoke.

krodda@gie.net

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