11 Feb 2021

Fixing environmental problems one plant at a time

From Our Changing World, 9:06 pm on 11 February 2021

David Leung finds ways to make plants solve environmental issues.

University of Canterbury researcher Negisa Darajeh has developed a powder that is very effective at removing nitrates from water and is now being considered for commercialisation.

University of Canterbury researcher Negisa Darajeh has developed a powder that is very effective at removing nitrates from water and is now being considered for commercialisation. Photo: Negisa Darajeh

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David Leung is a biotechnology researcher at the University of Canterbury.

He’s looking for “technology to help plants, to use plants and to develop better plants that can help deal with environmental issues.”

He’s a man of many ideas, and he has many students trying to bring those ideas to fruition.

Negisa Darajeh is developing a product that removes nitrates from water, for example from effluent treatment ponds on dairy farms.

She says she is using an abundant biowaste material as feedstock for her product, but isn’t able to divulge exactly what as the product is in the process of being commercialised.

At a lab scale the powder is very effective – and fast.

“Within 90 minutes we can remove 95 percent of nitrates,” she says.

It’s also very economical – just two grams per litre is enough to get rid of nitrates.

As well as fixing one problem, Negisa and David want to help in another area as well.

Once the nitrates have been removed, Negisa says the plan is to use the resulting powder as a slow-release fertiliser, reducing the need for synthetic fertilisers.

PhD student Trang Nguyen is developing potatoes that require just one sixteenth the amount of nitrate that potatoes usually need to thrive.

PhD student Trang Nguyen is developing potatoes that require just one sixteenth the amount of nitrate that potatoes usually need to thrive. Photo: RNZ / Alison Ballance

Trung Nguyen is culturing new potato breeds that will need less nitrogen to grow.

In the lab, she says, “the potatoes grow well and the nitrogen is like one sixteenth compared to the normal conditions.”

David says he is keen to supply the new efficient, low nitrogen potato to commercial growers for field trials.

Gowtham Janardhanan (left) is a PhD student developing cold tolerant crops in the University of Canterbury lab of plant biotechnologist David Leung.

Gowtham Janardhanan (left) is a PhD student developing cold tolerant crops in the University of Canterbury lab of plant biotechnologist David Leung. Photo: RNZ / Alison Ballance

Gowtham Janardhanan is developing plants with a strong cold tolerance, so they can survive lower winter temperatures. He’s intending to also develop peas that can tolerate high temperatures.

So far, his peas are doing well in a greenhouse, and the next step will be field trials.

Sabai Saw Shwe is a PhD student developing ways of growing wood in the lab.

Sabai Saw Shwe is a PhD student developing ways of growing wood in the lab. Photo: RNZ / Alison Ballance

Sabai Saw Schwe is working on ways to grow wood without growing trees.

David developed the idea after a conversation with the American Space Agency who are thinking ahead to building a space station on Mars.

Sabai has managed to convert stem calls from eucalyptus trees into xylem-like cells with strong cell walls, which David says is an excellent first step.

Listen to the full story to hear the team talk more about their work.

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