Brewers’ spent grain (BSG) is the main by-product of beer production, representing about 85% of brewing residues and amounting to nearly 40 million tonnes annually (8 million in Europe). As a continuous, non-seasonal biomass stream, it is a reliable resource for developing bio-based alternatives to fossil-based plastics. POLYMEER addresses this need by converting an abundant industrial residue into sustainable polymer systems. Following a cascading-use approach, the project targets the 20% of BSG that remains landfilled, without affecting its existing use as animal feed.
The consortium includes 14 partners from eight European countries, coordinated by the University of Perugia (Figure 1), covering the full value chain from raw material supply to biorefinery, polymer synthesis, scale-up, application testing and sustainability assessment. POLYMEER demonstrates a resource-efficient process that fractionates wet BSG without drying. Proteins are recovered first in line with the food-first principle, while cellulose, hemicelluloses and lignin are converted into new monomers and polymers using green chemistry. End-of-life (recyclability and biodegradability) is designed from the outset and supported by LCA, techno-economic and social-acceptance studies.
Developments focus on three application sectors: biodegradable mulch films for agriculture; bio-based polyesters for automotive textiles with improved UV resistance and recyclability; and recyclable or reprocessable materials for tertiary packaging, enabling breweries to create local circular loops (Figure 2).
POLYMEER follows a clear pathway from lab-scale research to pilot validation, ensuring that sustainability and safety-by-design guide material development. This creates the basis for large-scale BSG valorisation and supports Europe’s shift toward a circular, climate-neutral materials economy.
