Neoplants - Harnessing Plant-Microbe Interactions to Decontaminate Indoor Air

Neoplants worked for 5 years in R&D to develop their potted houseplant, the classic pothos (Epipremnum aureum), associated with a bioengineered Pseudomonas putida selected through directed evolution (cultured in pollutant-rich environment) to maximize their capture of air pollutants and conversion into biomass. The startup claims its product, Neo Px, removes indoor volatile organic compounds (VOCs) up to 30 times better than any houseplant.

Neoplants is based in France but makes and sells the product in the USA, at 99 $ the houseplant, with its pot and 3 Power Drops, the recharges of partner microbes, to be added once a month. A subscription model is also possible, delivering the Power Drops recharges every three months for a recurring 39 $ fee (here ).

The pot ("shell") was designed to optimize air flow and includes a water tank to water the plant only every 2-3 weeks.

Neoplants' innovation is to have bioengineered air-purifying bacteria that live in association with pothos, to capture, filter and convert VOCs (benzene, toluene, ethylbenzene and xylene) into organic matter, delivering purified air for a surface of about 160 square feet per plant (15 square meters).

Why Pothos? Why Pseudomonas putida?

Pothos is a houseplant known for its bioremediation abilities, absorbing significant amounts of VOCs, and coding for the enzymes able to degrade them into plant's building blocks.

For the microorganisms, there was more work to do for the selection. The researchers say they tested dozens of carefully selected bacteria and fungi able to use different VOCs as carbon sources. They found one able to utilize the VOCs as its sole carbon source, which also proved able to associate with the plant, and exerted beneficial effects for the plant's health.

Pseudomonas putida is a known species often used as a biostimulant for its stimulation of root growth, solubilization of phosphate and iron in soils, and decontamination of hydrocarbons.

Directed Evolution

To obtain up to 30 times the depollution benefits compared to common houseplants, Neoplant's R&D team exposed hundreds of billions of selected bacteria to liquid VOCs in concentrations slightly higher than the initial level for these bacteria. The few ones that survived were multiplied and exposed to the same cycle dozens of times over 5 years to create organisms adapted to the bioremediation of VOCs at high concentration. This is the same idea as the famous Harvard video showing the quick evolution of bacteria exposed to increasing concentrations of antibiotics - but with liquefied volatile pollutants.

Why I Like the Approach

We spend over 90% of our time indoors, and indoor air is up to 5 times more polluted than outdoor because of solvents and varnishes from paint, furniture, textiles and cleaning products. This can lead to airway symptoms including fatigue, headaches, asthma, allergies, eye and throat irritation, cancer, and cognitive function impairment (the scientific references are available in Neoplant's white paper ).

The website includes a questionnaire to estimate air quality in your bedroom, on the basis of your aeration habits, type of wall and floor cover, smoking, candle use and cleaning frequency.

The system was tested in a leak-proof chamber inoculated with toluene at 120 ppb (parts per billion). A standard pothos stabilized the air at about 110 ppb, while the inoculated pothos stabilized it to a level of 90 ppb. Peace lily, spider plant and snake plant, also known as NASA's depolluting house plants, showed almost no cleaning capacity. Indeed, more recent data has shown that to efficiently improve air quality, we should use 10-1000 plants per square meter! Keeping house plants still has its benefits, as shown in a recent publication regarding the benefits of urban gardening on immune regulation and skin microbiota - but the quality of soil matters, in particular, its microbial richness!

Limitations of the Offer

Lack of Evidence in Real Setting

My main issue with the science presented is the data was generated in a small air-tight chamber that is not representative of the conditions in which the product is claimed to offer benefits : a room of about 15 m2. In human healthcare and agriculture, companies are asked to provide evidence of their solutions' benefits in the target host or setting. I want to see the data for a room with representative standardized parameters, before adding the plant (or using a standard pothos) and after using the Neo Px plant, and really hope the startup will go in that direction soon.

Scientific Dissonance

On the website, the company claims that the organisms they have selected can only use VOCs as carbon sources. Then in the white paper they mention that the Power Drops include the Pseudomonas putida cells and everything they need to thrive. Wait... are there pollutants included in there? Or other nutrients? Does that include plant nutrition? Should we proceed as with common houseplants, with a fertilization cycle about every month in the growth period? If so, shouldn't that suffice the microorganisms?

Lack of Transparency on Stability

The strain was selected for its incredible duration and ability to associate with the plant long-term. But it's recommended to inoculate it every month. That's not a problem, but if the company decided for a monthly reload, I'd like to see the data showing the stability data and duration of reload in the recommended conditions of care.

Cross-selling

My understanding is that the technology is mostly based on the directed evolution for the Pseudomonas putida, while the pothos is a classical house plant. I wish the company could sell the microbial drops without having to spend the initial 99$ on a house plant with aerated pot. I have two pothos and they are very easy to propagate. They are quite slow growers, but after some time, they ask for a bigger pot. I wish I could simply use the bacterial drops in their watering every month.

Trying to even sell the plant footer at check-out tells me the company is not into a model of sober, regenerative economy, in dissonance with the efforts for creating a pot from eco-friendly materials.

Geography

A big limitation is the availability, currently only in the US. I do not know if this is linked to the business model and profitability scheme, shipping difficulty of live plants, or due to regulatory reasons given that the directed evolution is neither GMO nor naturally-occurring, a grey area for which the US is a more-friendly territory than Europe for example.

Disclaimer

This newlsetter is based on the information available from Neoplant's website and white paper, which I have chosen to share freely and without any incentive.

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