Lorena Germán ^1* Rubén Cobos ¹ Leire Lorenzo ² Francisca Río ² Soraya Prieto ² Tomás Roncal ¹ José María Cuevas ¹

• ¹ GAIKER Technology Centre, Zamudio, Spain
• ² Tecnalia Research & Innovation, San Sebastian, Spain

Within the context of the circular economy, transformation of agri-food wastes or by-products into valuable products is essential to promote a transition towards more sustainable and efficient utilization of resources. Whey is a very abundant by-product from manufacturing dairy products. Apart from partial reutilisation in animal feed or some food supplements, the sustainable management and disposal of whey still represents a big environmental issue.In this work, considered whey as a valuable resource for producing high-value products, 2,3butanediol (2,3-BDO) was produced by fermentation using the bacterial strain Lactococcus lactis 43103. The described process yielded >90% purity 2,3-BD that was evaluated as a potential chain extender in the synthesis of biobased waterborne polyurethane dispersions (PUD).The incorporation of whey-derived 2,3-BDO led to designing up to 90% biobased content PUD without detrimental effect on the process and the liquid phase properties. The combination of 100% biobased polyether polyols with partially renewable L-lysine ethyl ester diisocyanate and whey-derived 2,3-BDO as chain extender generated totally stable low particle size water dispersions of amorphous polymers characterised by similar structure and molecular weight than those of alternative petroleum-based PUD. These results open up the possibility of incorporating fermentation-derived 2,3-BDO as a totally renewable component in biobased PUD as potential sustainable resinous systems for further formulation of water-based coatings or adhesives.