Meet the researcher: Growing a grassroots protein revolution with Mette Lübeck

The protein found in grass is the most abundant on Earth – so why don’t we eat it? Mette Lübeck and her team are putting this humble plant at the heart of a project aiming to transform the global protein supply.

Mette Lübeck works with clover grass to extract protein
Associate professor Mette Lübeck
Credit: Lars Horn
Associate professor Mette Lübeck
Credit:Lars Horn

Name:  Mette Lübeck

Job title: Associate Professor 

Organisation: Aalborg University 

Sustainable protein specialism: Plant-based, fermentation

A humble plant that grows in abundance across the planet is at the heart of a project aiming to transform the global protein supply.

Mette Lübeck is leading a team at Aalborg University in Denmark which aims to extract a high-quality protein from grass. If successful, the technique has the potential to turn the stuff growing beneath our feet into a valuable ingredient for the plant-based food industry, provide farmers with new sources of income and create jobs in rural areas.

The initial aim was to create a sustainable alternative to soy-based animal feed imported from South America, but the team quickly realised there were opportunities to take the project much further – with Mette’s inspiration coming from the dairy industry.

“In the old days, whey protein was a useless waste stream,” she said. “But then the industry worked out how to use membrane filtration to recover it from milk. Now, it’s more valuable than the rest of the cheese they produce, so we thought we could use the same system to extract protein from grass.”

Working with the university’s membrane specialists, the team are developing a process for extracting rubisco – a naturally occurring protein used by green-leaved plants for photosynthesis.

Goodness in the green, green grass of home

The technique involves screw-pressing the grass to produce juice, which is then separated into a green liquid that can be used for animal feed and a higher-quality clear liquid for humans – before being filtered to remove salts and sugars.

The resulting rubisco powder forms a complete protein, meaning it contains all nine amino acids required for human nutrition. But, unlike commonly used protein isolates like soy or pea – which are acidic – it has a neutral pH level.

This, she says, makes it an attractive and versatile option for producers, and food experts from Copenhagen University are now looking into how it can be used as an ingredient to add new properties to products.

Field of dreams

“We’re really thinking of circularity and getting all the nutrients from what we produce,” she adds. The process will continue to yield locally produced animal feed as a secondary product, while waste materials can be used for biorefining. And, as part of a separate project, she aims to use other proteins left over from the filtration process as a feedstock for developing fermentation-based foods.

Because the clover grass the project focuses on grows from spring until autumn, Mette envisages a system in which 500 hectares of land would produce enough crops to press up to 20 tonnes per hour, over more than six months of the year.

This would mean benefits for the climate – as the grass would sequester carbon while it grows – and for local economies. Because fresh grass is required, small processing plants would need to be set up close to where it is grown, providing jobs in rural areas.

Mette believes the process can be applied to a wide variety of plants, from sugar beet to alfalfa, meaning the system could be replicated in virtually any part of the northern hemisphere.

So far, the project has been developed at lab scale, but Mette now plans to scale it up with BiomassProtein, the spin-out company she founded with her husband, biochemist Peter Stephensen Lübeck.

As well as overcoming the considerable infrastructure challenges, the team would also require regulatory approval before the protein can be used in the EU, so are beginning to gather the data required to make an application under the Novel Foods Regulation.

Branching out

Mette, who initially studied plant diseases at an agricultural university before becoming an associate professor in chemistry and biosciences, says the diversity of the multidisciplinary team – with plant experts working alongside engineers and food scientists – is key to the project’s success.

And she believes collaboration is essential for researchers who want to work in the alternative protein space.

“You have to be passionate about doing something good for the climate and how you can make our food system more sustainable,” she said. “Try to engage with people from different backgrounds because, together, you can come up with very new and interesting ideas.”

Find out more about the potential for rubisco in alternative proteins
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