Can a genetically modified plant clean the air in your home?
A house plant has been genetically modified to break down indoor pollutants

Mark Stone/University of Washington

If you live in Canada, you might soon be able to buy a genetically modified fluorescent houseplant that removes cancer-linked pollutants such as benzine from the air in your home. A team in the US has just received approval to sell the houseplant there.

The plant is known as golden pothos or Devil’s ivy (Epipremnum aureum), a widely grown houseplant that can tolerate low light levels and extreme neglect. It has been modified to produce a liver enzyme called cytochrome p450 2e1 – taken from rabbits – that breaks down a wide range of pollutants.

“We want to offer this to the public as a way to reduce a proven, real health threat,” says Stuart Strand of the University of Washington in Seattle.


Glowing houseplants

The transgenic plant also produces a green fluorescent protein that glows under UV light. This is to make it more appealing, and also to make it easy to spot the GM variety.

The team has just published a study showing that when placed in a container with high levels of either benzene or chloroform, normal pothos plants broke down less than 10 per cent in a week. The GM variety broke down more than 90 per cent.

Even so, a fan would be needed to maximise the clean-up effect in homes. “The plants are not going to do much good sitting in a corner,” says Strand. “They need to have air moving over them.”

Benzine is a known carcinogen that can get into homes in many ways, including from cars in adjacent garages or from burning candles. Chloroform is a suspected carcinogen released by chlorinated water during activities like showering.

The air in our homes is full of many other pollutants, from furnishings, heating and cooking. It’s often claimed normal houseplants reduce indoor air pollution, but researchers say in practice a few plants make little difference. “Yes, plants can remove pollutants, but it is unlikely to have a major impact on indoor air quality,” says Nicola Carslaw of the University of York, UK, who studies indoor air chemistry.

Indoor pollutants

Clive Shrubsole of Public Health England agrees. “Most studies indoors seem to indicate that plants alone have little or no impact on indoor pollutants,” he says.

What’s more, studies often involve exposing pot plants in soil to very high pollutant levels. Strand thinks this leads to population explosions in pollutant-eating microbes in the soil, and that the plants themselves do little. He grew sterile plants in hydroponic solutions without soil to exclude this possibility in his tests.

Would it be simpler just to open a window? “Oh, yes, sure,” says Strand. Improved ventilation is the best way to reduce indoor air pollution, he says, and heat exchangers are now available that can keep houses well ventilated in winter without massive heating bills. But Strand still thinks there’s a place for the GM plants as another line of defence. “It’s almost a no-brainer,” Strand says.

Pothos cannot grow outside in Canada. But it does in southern Florida, so to get approval in the US the team has to first show that the GM pothos is no more likely to cause problems as a weed than normal pothos.

Journal reference: Environmental Science & Technology, DOI: 10.1021/acs.est.8b04811

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