Money plant. Photo: iStock
Money plant. Photo: iStock

Now, GM ‘money plant’ to reduce indoor pollution

According to researchers, a hypothetical bio-filter made of these transgenic plants could deliver cleaner air than commercial home particulate filters

New Delhi: Houseplants have long been used to reduce indoor air pollution levels, but research shows they do not completely remove some of the toxic air pollutants present inside houses.

To address the challenge, scientists from the department of civil and environmental engineering, University of Washington, introduced a mammalian gene CYP2E1 to a common houseplant, pothos ivy (Epipremnum aureum), locally known as the ‘money plant’, to boost the plant’s detoxifying potential.

The modified plant has a protein called cytochrome P450 2E1, which converts these compounds into molecules that plants can then use to support their own growth. The team then injected benzene and chloroform gas into closed vials that contained growing plants to test them for 11 days.

“After three days, the concentration of chloroform in vials dropped by nearly 82 % and was barely detectable on the eighth day. The concentration of benzene also decreased in the modified plant vials, but more slowly," according to the research team. Concentrations of compounds in vials containing unmodified ivy, however, showed no change.

“It is an example of the ‘green liver’ concept," said professor Stuart Strand, the senior author. “People haven’t really been talking about these hazardous organic compounds in homes and I think that’s because we could not do anything about them. Now we have engineered houseplants to remove these pollutants for us," he said.

The entire process took more than two years. “That is a long time, compared to other lab plants, which might take only a few months. However, we wanted to do this in pothos because it’s a robust houseplant that grows well under all sort of conditions," said lead author Long Zhang. It also does not flower, so there is no risk of releasing transgenes into the environment.

The research has been published in the ‘Environment Science and Technology’ journal.

The research is significant as air inside homes often contain hazardous volatile organic compounds such as chloroform, which is present in small amounts in chlorinated water, or benzene, a component of gasoline. These build up in houses when we shower or boil water, or when we store cars or lawn mowers in attached garages. Both benzene and chloroform exposure have been known to be carcinogenic to vulnerable population such as children.

Various house plants have the ability to remove volatile organic compounds from air, but their uptake rates vary significantly. “Plants in a house would need to be inside an enclosure with something to move air past their leaves, like a fan. If you had a plant growing in the corner of a room, it will have some effect. But without air flow, it will take a long time for a molecule on the other end of the house to reach the plant," according to Professor Strand.

The team is currently working to increase capabilities of transgenic plants by adding a protein that can break down another hazardous molecule found in air in houses, including the most toxic formaldehyde, which is present in some wood products, such as laminate flooring and cabinets and tobacco smoke.

Researchers estimate that a hypothetical bio-filter made of these transgenic plants could deliver cleaner air than commercial home particulate filters. However, more work is needed to establish its practical applications.