Pothos Ivy just got a remake and will now remove benzene and chloroform from the air around it! Researchers at the University of Washington genetically modified this common houseplant and the resulting plant can clean these two pollutants which are hazardous compounds that are too small to be trapped in HEPA air filters.
Benzene which is a component of gasoline can build up in homes when we store lawn mowers and cars in attached garages. Even burning candles produce this compound. Chloroform is present in small amounts in chlorinated water and can be released when we take showers or boil water. Both compounds have been found to be linked to cancer. They aren’t commonly talked about because previously nothing could be done about them in our homes.
The modified Pothos Ivy plants express a protein called 2E1 which will transform these compounds into molecules which the plants will then use to support their growth. The process took 2 years and while other lab plants might only take a few months to achieve the intended results, the team chose the pothos because it is a robust houseplant that grows very well under a variety of conditions.
The researchers used a protein called cytochrome P450 2E1 or 2E1 for short, which is present in all mammals including humans. This protein turns chloroform into carbon dioxide and chloride ions and turns benzene into a chemical called phenol. However, 2E1 is located in our livers and is actually turned on when we consume alcohol. It is not available to us to help us process any pollutants in the air.
The team decided to have this reaction occur outside the body in a plant which they call an example of the “green liver” concept. The p450 2E1 cytochorme was taken from rabbits. It was then introduced into the pothos ivy so that each cell would express the protein. Pothos ivy does not flower in temperate climates so the genetically modified plants would not be able to spread via pollen.
They then tested how well the modified plants could remove the two pollutants from air compared to how well normal pothos ivy would preform. Both types of plants were put in glass tubes and then either chloroform gas or benzene was added. Over the following 11 days the team tracked how the concentration of each pollutant changed in the tubes.
The concentration of chloroform gas did not change over time in the unmodified plants. But the concentration of chloroform dropped by 82 percent after three days in the modified plants. And by the sixth day was almost undetectable. The benzene concentration also decreased in the modified plants, however more slowly. By the eighth day though the benzene concentration dropped by almost 75 percent. Normal pothos ivy only broke down less than 10 percent in the first week.
The team did use much higher pollutant concentrations that would typically be found in homes so they could detect changes. They anticipate that the levels of the two pollutants would drop similarly in homes and perhaps even faster over the same time frame.
If used in the home, the plants would need to be inside an enclosure with something to move the air past the leaves such as a fan. A plant sitting in a corner will have some effect on that particular room, but without airflow it would take a longer time for a molecule on another side of the room to reach the plant. And the transgenic plant also produces a green fluorescent protein that glows under UV light. This was added to make the plant more appealing and also to make it easy to spot!
The research team is now working on increasing the plants capabilities by adding a protein which can break down another hazardous molecule found in homes which is formaldehyde. This compound is present in some wood products such as laminate flooring and cabinets and in tobacco smoke.
All these hazardous compounds are very hard to get rid of. Without proteins to break down the molecules, high energy processes would have to be used. It makes more sense, is simpler and more sustainable to put the proteins all together in a common houseplant. And 2E1 is beneficial to the plant since they use chloride ions and carbon dioxide to make their food, and they use phenol to help make components of their cell walls.
The plant may soon be available in Canada where it does not grow outside. However it does grow in southern Florida so to get approval in the United States the research team has to show that the genetically modified pothos plant is no more likely to cause problems as a weed than regular pothos. Until it is available spider plants remove many pollutants so can be used in homes to help purify the air.
To view the original scientific study click here: Greatly Enhanced Removal of Volatile Organic Carcinogens by a Genetically Modified Houseplant, Pothos Ivy (Epipremnum aureum) Expressing the Mammalian Cytochrome P450 2e1 Gene. Environmental Science & Technology, 2018; DOI: 10.1021/acs.est.8b04811