On track to produce better lab-grown burgers

(Press-News.org) Beef is growing in the Petri dishes of ETH professor Ori Bar-Nur, an expert in regenerative and muscle biology. However, he hasn’t yet tasted the cultivated meat because human consumption requires official approval in Switzerland. However, Bar-Nur has colleagues who have participated in approved tastings of lab-grown beef. They describe the taste and consistency as being similar to that of real meat. After all, it is beef, the only difference being that no cow needs to be slaughtered in order to obtain it.

Bar-Nur and his team produce the meat in cell culture from bovine cells. They use precursor cells, known as myoblasts, that form muscle fibres. These cells can be obtained by taking a biopsy from a living cow. For their research, however, they isolated the cells from standard beef cuts: fillet, sirloin, cheek and flank.

Not so easy with beef Although scientists had previously succeeded in generating muscle fibres from bovine myoblasts in the lab, these fibres were usually quite thin.

The ETH researchers have now succeeded in creating three-dimensional muscle tissue composed of thick fibres from myoblasts. This tissue also more closely resembles natural bovine muscle tissue at the molecular and functional levels; it has the same genes and proteins active as natural bovine muscle tissue and contracts similarly to its natural counterpart. This was not the case for muscle tissue produced using the previous method; the cells lacked some of the proteins found in natural muscle.

Lab-grown chicken available in Singapore With his research, Bar-Nur is working in a field with a promising future – one that aims to revolutionise meat production. Around the world, dozens of start-ups are racing to develop affordable lab-grown meat, anticipating customer demand for meat production without the need for cow sheds, livestock transportation and abattoirs. Furthermore, this kind of meat requires less land for its production. It may also be more climate-friendly, although this remains a subject of debate.

In Singapore, chicken produced in the lab from cultured animal cells is already commercially available. In the case of lab-grown beef, development has yet to reach that stage. The ETH findings could now accelerate developments in this area.

A cocktail of three molecules To produce thick and functional muscle fibres, the ETH Zurich researchers added a cocktail of three molecules to the cell culture medium – the nutrient-rich liquid used to grow cells in lab dishes. The added molecules play a key role in cell differentiation. Bar-Nur originally developed the cocktail seven years ago during his postdoctoral work at Harvard University.

Back then, he was working mainly with mice. His basic research revolved around cultivating muscle cells outside of the body for the treatment of hereditary diseases involving muscle degeneration. Research into muscular dystrophy continues to be a key focus for Bar-Nur at ETH Zurich. Moreover, he has discovered that his approach involving the three molecules is suitable for producing superior cow muscle cells in the lab.

Ultimately clean and safe The three molecules are only required in the early stages of muscle fibre formation. After that, it is possible – and necessary – to remove the molecules from the cell culture medium during the production process. Any future commercial product would not contain them.

Still, additional development is necessary to reach market maturity. “The cell culture medium requires further optimisation to make it more affordable and safe for consumption. Additionally, we need to explore ways to produce these muscle fibres in larger quantities,” says Christine Trautmann, a doctoral student in Bar-Nur's group and one of the two lead authors of the study. So far, the researchers have only produced a few grammes of muscle, but they are now exploring ways to scale up production.

“These innovative new food products will have to undergo a prolonged and complex authorisation procedure before they reach shop shelves and, ultimately, our plates,” explains Adhideb Ghosh. He is a scientist in Bar-Nur's group and the other of the two lead authors of the study. With a view to developing this technology further and bringing it to market, ETH professor Bar-Nur is considering launching a start-up company. He wants to help ensure that we will one day be able to produce ethically sound burgers that are affordable and safe.

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