One person's trash is another's treasure : assessing the life cycle sustainability of bio-based innovations in brewery by-product valorisation

Agricultural residues and by-products are often not valorised and still considered waste rather than a valuable resources. Recognising their potential enables the adoption of a biorefinery approach to produce high value-added products. Beer production holds significant potential for utilising residues and by-products. In Europe alone, 346 million hectolitres of beer were produced in 2023, generating 20 kilograms of by-products and waste streams per hectolitres, including brewer's spent grains (BSG), spent yeast, wastewater, and CO2 from fermentation. The Horizon Europe project CHEERS leverage these underutilised residues and by-products of beer production to create five competitive and innovative bio-based products, namely insect protein powder (1), single-cell protein (2), volatile fatty acids (3), chlorine (4), and ectoine (5). Insect protein is produced by feeding brewer’s spent grains to mealworms, while the other four products are derived through microbiological processes. Carbon dioxide from beer fermentation serves as an input for these processes. Together with methane from the anaerobic digestion of wastewater, it is used to produce single-cell protein (2) and volatile fatty acids (3) as ingredients for pet food, chlorine (4) for disinfectants, and ectoine (5) for cosmetic products. Foreground data on the life cycle of these bio-based refineries was collected to conduct a cradle-to-grave life cycle sustainability assessment (LCSA). The results were compared with reference products made from fossil-based materials, enabling a discussion of synergies and trade-offs. The project seeks to develop a holistic understanding of the environmental, economic, and social impacts associated with the evaluated products. An initial screening LCA revealed that high energy consumption is the primary driver of environmental impacts in bio-based production at the pilot scale. These findings were further refined through validation using up-scaling (ex-ante) scenarios. At the LCM 2025 conference, the environmental, economic, and social impacts of this bio-based economy will be presented, alongside various ex-ante scenarios.