Heriot-Watt scientists turn dairy waste into fuel

A company that helped design how astronauts grow and recycle food in space is working with Heriot-Watt University to tackle the problem of dairy waste here on Earth.

Take Root Bio worked with the International Centre for Brewing and Distilling (ICBD) to successfully turn salty whey, a high-volume by-product from cheese production, into a widely used fuel called bioethanol.

Supported by the Industrial Biotechnology Innovation Centre (IBioIC), which connected the two organisations through its industry network, the project brought together Take Root Bio’s closed-loop approach with Heriot-Watt’s expertise in bio-based solutions.

Together, they looked at how the sugars found in salty whey could be transformed through a bio-based process, creating value from a material that is often difficult and costly to manage. The process also leaves behind a secondary stream that could potentially be recovered and reused.

The challenge of disposing of salty whey is significant. Around 95,000 tonnes are generated in the UK each year from production of cheddar and similar cheeses, and its combination of milk sugars and high salt content makes management particularly difficult.

A single dairy producer can generate tens of thousands of litres every week, creating both environmental and economic pressures for the sector.

While the project focuses on dairy waste, the thinking behind it comes directly from the Take Root’ Bio’s background in biosphere engineering and complements Heriot-Watt’s circular economy expertise. In the kinds of systems Take Root develops, resources are kept in use for as long as possible, with one process feeding into the next rather than creating waste.

That same thinking runs through Heriot-Watt's side of the project. Its scientists specialise in finding new value in food and drink by-products. They use biological processes to turn difficult materials into usable resources, making the partnership a natural fit

At the heart of the project was the idea that salty whey could be treated as a resource rather than waste, meaning dairy producers could potentially reduce the costs associated with its management while providing feedstock for new bio-based products. The company is also looking at whether mobile production units could be deployed closer to where these by-products are produced, helping to reduce transport requirements and making the concept easier to scale.

Kirk Siderman-Wolter, founder of Take Root Bio, said: "We've always been interested in what happens when you stop looking at something as waste and start asking what else it could become. The company began by looking at how people might grow food in space, where every resource matters and nothing can be thrown away. The same principles apply surprisingly well here on Earth. Salty whey is produced in huge volumes and can be difficult to deal with, so we wanted to find out whether there was a better use for it.

"If we can help turn something that currently costs money to manage into something with real value, that's a positive outcome for both dairy producers and the environment."

Heriot-Watt has taught and researched brewing and distilling since 1903 and is also developing plans for a new Centre for Sustainable Brewing and Distilling to help the sector address environmental challenges and support more sustainable ways of working. The centre will give the sector access to low carbon testbeds, support for bringing new products to market and training for the next generation of industry talent.

The research carried out at ICBD reflects Heriot-Watt's wider focus on the circular economy and resource efficiency, both key strands of iNetZ+, the University's Global Research Institute for Net Zero and Beyond.

Dr Jane White, an expert in waste valorisation at Heriot-Watt University, said: "Food and drink manufacturing produces a huge range of by-products, many of which still contain valuable components but can be challenging to manage. That makes them interesting candidates for bio-based processes that can recover value from materials that might otherwise be treated as waste."

Dr Shiwen Zhuang, specialised in fermentation development at Heriot-Watt University, said: "This project gave us the opportunity to explore whether bio-based solutions could help unlock some of the value in salty whey while reducing the pressures associated with disposal. It's exactly the kind of upcycling approach that could strengthen sustainability across the food and drink sector."

Dr Liz Fletcher, director of impact and deputy CEO at IBioIC, said: "One of the biggest opportunities in industrial biotechnology is finding new uses for materials that are currently treated as waste. By bringing together businesses and academic expertise, projects like this can uncover solutions that deliver both environmental and commercial benefits.

"What we liked about this project was that it approached a familiar problem from a different angle. That's exactly the sort of innovation we want to support, and we're excited to see where the work goes next."

Looking ahead, Take Root Bio and Heriot-Watt will investigate whether similar techniques could be applied to other food and agricultural by-products, including waste from fruit and vegetable processing.