Bioethanol from salted whey: a new method for processing cheese-making waste

During the production of Cheddar and similar cheeses, salted whey is generated — a liquid byproduct that is difficult to process or dispose of due to its high salt content (from 4% to 10%) and organic matter. Discharging it into water bodies harms aquatic ecosystems, while its application to soil degrades the health of crops and land. In the UK alone, about 95,000 tonnes of such waste are produced annually, with individual dairy producers generating tens of thousands of liters weekly.

British biotechnology company Take Root Bio and specialists from the International Centre for Brewing and Distilling at Heriot-Watt University (supported by the Industrial Biotechnology Innovation Centre, IBioIC) have created a bioprocess that turns sugar from salted whey into bioethanol. Traditionally, high salt concentration hindered whey fermentation, but the researchers successfully applied a bio-based method. The technology also generates a second residual stream suitable for recovery and reuse.

Technical details of the process have not yet been publicly disclosed: the developers do not report the microorganism used, the salt level, the fermentation parameters, or the volume of ethanol obtained. Nevertheless, if the technology proves economically viable on a large scale, it will allow dairy farms to reduce liquid waste disposal costs.

Kirk Cidermand-Wolter, head of Take Root Bio, noted the urgency of finding new applications for materials previously considered waste. In turn, Dr. Shiwen Zhuang, a fermentation specialist at Heriot-Watt University, emphasized that the project made it possible to explore the potential of bio-solutions for extracting value from salted whey and reducing the burden of its disposal.

To reduce logistics costs, Take Root Bio is considering the creation of mobile units directly next to dairy production facilities. In addition, the collaborators are exploring the possibility of applying similar methods for processing fruit and vegetable processing waste, and plan to capture gases (including methane and hydrogen) generated during fermentation for further use in food production.