Scientists brew up a new way to grow meat

Peer-Reviewed Publication

University College London

Yeast left over from brewing beer can be transformed into edible ‘scaffolds’ for cultivated meat – sometimes known as lab-grown meat – which could offer a more sustainable, cost-effective alternative to current methods, according to a new study from UCL (University College London) researchers.

‘Nose to tail’ eating, which emphasises the use of the whole animal, has long been an ethos of sustainability-conscious chefs and diners. But as cultivated meat comes closer to supermarket shelves, a new innovation could see a ‘pint to plate’ approach to serving up burgers and steaks.

The new study, published in Frontiers in Nutrition, explores how bacterial cellulose grown from yeast left over from brewing beer can be used to grow cultivated meat, an emerging form of food production that grows animal cells on an edible scaffold in the lab.

In nature, cellulose is a hardy substance that gives structure to plant cells. Similarly, bacterial cellulose is created by microbes to create a protective layer around the organism’s cells.

Historically, bacterial cellulose has been used to make nata de coco, a jelly-like dessert from the Philippines. But in recent years, improvements in cultivating both plant and bacterial cellulose have seen their useful properties applied to everything from plant-based foods to 3D-printed bandages.

Now researchers believe that bacterial cellulose may be able to help solve the challenge of creating affordable, edible scaffolds that replicate the texture and structure of animal tissue to grow animal cells on, which has hampered the cultivated meat industry’s ability to scale up and bring products to market.

One untapped source of bacterial cellulose is brewer’s spent yeast, a by-product of beer fermentation that often ends up being thrown away.

Professor Richard Day, senior author of the study from UCL Division of Medicine, said: “Cultivated meat has the potential to revolutionise food production, but its success depends on overcoming key technical challenges.

“While it’s relatively easy to grow animal cells for mass food production you need to be able to grow them on something cheap, edible and that preferably provides a structure that resembles real meat.

“Our research shows that brewing waste, which is often discarded, can be repurposed to grow bacterial cellulose with properties suitable for meat scaffolding. This could significantly reduce costs and environmental impact.”

For the proof-of-concept study, researchers from UCL collected spent yeast from the Big Smoke Brewing Company in Esher, Surrey, and used it to culture Komagataeibacter xylinus, a bacterium known for producing high-quality cellulose.

The resulting cellulose was tested using a ‘chewing machine’ – a probe that repeatedly compresses a substance while measuring forces like chewiness, hardness and stickiness – to assess its structural and mechanical properties.

The team found that when used in place of a conventional nutrient broth used for growing the bacteria, the beer waste produced bacterial cellulose of equal quality, which was actually closer in texture to natural meat products, with lower hardness and chewiness than ‘standard’ cellulose.

Most importantly, when animal cells (fibroblasts, a cell type found in meat) were placed on the beer waste-derived scaffold they attached to it, indicating that the material can support cell growth for cultivated meat production – though the researchers stress that the project is at an early stage and further work is needed.

The team plan to further develop the approach by incorporating other cell types found in natural meat, such as fat and muscle cells. They also plan to test spent yeast from different types of beer to assess bacterial cellulose yields and the quality of the resulting scaffolds.

Christian Harrison, the study’s first author and a PhD student from UCL Division of Medicine, said: “One of the biggest hurdles in cultivated meat is replicating the ‘mouthfeel’ and texture of real meat. Our findings suggest that bacterial cellulose grown on brewing waste not only supports cell growth but also mimics the mechanical properties of meat more closely than other scaffolds.

“This opens up exciting possibilities for scalable, sustainable meat alternatives. In this study we collected a relatively small amount of raw material from one craft brewery, that would otherwise have gone to waste. But huge volumes of brewing waste are generated each year that could have a valuable use.”

This research was supported by the Biotechnology and Biological Sciences Research Council (BBSRC).