Periodic Reporting for period 1 - POLYMEER (BREWERS SPENT GRAIN AS MAIN BY-PRODUCT FOR DEVELOPMENT OF NOVEL, HIGH-PERFORMANCE BIO-BASED POLYMERS, POLYMER BLENDS, AND CO-POLYMERS)
Reporting period: 2024-09-01 to 2025-08-31
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.
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.
During the first reporting period, POLYMEER strengthened the scientific and technical foundations for converting BSG into new bio-based polymer systems and preparing scale-up. Two wet-fractionation processes for fresh BSG were optimised, enabling efficient recovery of proteins, cellulose, hemicelluloses (mainly arabinoxylans) and lignin without drying. Proteins were extracted first, while a reactive-extraction route enabled simultaneous isolation and functionalisation of arabinoxylans. Early scalability checks confirmed compatibility with upcoming pilot trials.
A first structured library of bio-based building blocks was compiled, integrating newly synthesised intermediates and commercial references. Synthetic pathways were designed following green-chemistry principles, with reduced solvents and safer reagents. Progress was achieved in producing new polymer systems, including the first series of lactone/phospholane copolyesters and phosphorus-based polymers as early-stage building blocks. Work also began on vitrimeric materials for tertiary packaging and on defining performance and processing requirements for target applications. Sustainability work included a chemical inventory and hazard screening, an environmental hotspot analysis, and a literature review on social acceptance.
A first structured library of bio-based building blocks was compiled, integrating newly synthesised intermediates and commercial references. Synthetic pathways were designed following green-chemistry principles, with reduced solvents and safer reagents. Progress was achieved in producing new polymer systems, including the first series of lactone/phospholane copolyesters and phosphorus-based polymers as early-stage building blocks. Work also began on vitrimeric materials for tertiary packaging and on defining performance and processing requirements for target applications. Sustainability work included a chemical inventory and hazard screening, an environmental hotspot analysis, and a literature review on social acceptance.
A major accomplishment of POLYMEER is the validation at lab scale of a refined patented route and a complementary process for resource - efficient f ractionation of wet BSG, which are unique compared to the conventional methods. In addition, several of the pathways identified for the creation of the first library of bio-based building blocks represent previously unreported sustainable synthetic approaches and are currently undergoing optimisation. This limits the reliance on hazardous substances.
The incorporation of phosphate units into the lactone-based polyester backbone represents a novel concept within bio-based polymer systems and broadens the design space for materials with tailored degradation behaviour. Initial work on vitrimeric systems for tertiary packaging marks an exploration into an emerging class of reprocessable materials with potential relevance for future circular packaging concepts.
Taken together, these achievements lay the scientific and technological foundation for the development of more sustainable, circular polymer systems (Figure 3).
From an economic and circular-economy perspective, the technologies developed in POLYMEER create new opportunities for regional value-chain integration between breweries, biorefineries and polymer-processing industries. The approach offers a replicable model for the local valorisation of an abundant agro-industrial side stream. Social sustainability aspects have also been considered through preliminary hazard-screening activities and a literature-based assessment of social acceptance factors relevant to bioplastics.
While measurable impacts will only materialise in later project stages, the alignment of material development with industrial requirements increases the likelihood of future uptake. To ensure further progress, several enabling factors are identified: the need for pilot-scale validation in the next phases of the project; continued optimisation of the cost and performance of BSG-based materials; protection of intellectual property; alignment with evolving biodegradability and safety standards; and ongoing collaboration within the CBE JU community and with sister projects, to support knowledge exchange and future market readiness at the European level.
The incorporation of phosphate units into the lactone-based polyester backbone represents a novel concept within bio-based polymer systems and broadens the design space for materials with tailored degradation behaviour. Initial work on vitrimeric systems for tertiary packaging marks an exploration into an emerging class of reprocessable materials with potential relevance for future circular packaging concepts.
Taken together, these achievements lay the scientific and technological foundation for the development of more sustainable, circular polymer systems (Figure 3).
From an economic and circular-economy perspective, the technologies developed in POLYMEER create new opportunities for regional value-chain integration between breweries, biorefineries and polymer-processing industries. The approach offers a replicable model for the local valorisation of an abundant agro-industrial side stream. Social sustainability aspects have also been considered through preliminary hazard-screening activities and a literature-based assessment of social acceptance factors relevant to bioplastics.
While measurable impacts will only materialise in later project stages, the alignment of material development with industrial requirements increases the likelihood of future uptake. To ensure further progress, several enabling factors are identified: the need for pilot-scale validation in the next phases of the project; continued optimisation of the cost and performance of BSG-based materials; protection of intellectual property; alignment with evolving biodegradability and safety standards; and ongoing collaboration within the CBE JU community and with sister projects, to support knowledge exchange and future market readiness at the European level.