Comparative LCA of feather treatment processes (Steam Explosion, Microbial Fermentation, Mechanical Grinding) for sustainable bioplastic feedstock production

Poultry feathers represent a substantial keratin-rich waste stream with potential for valorisation into bio-based materials. This study evaluates the environmental performance of three novel feather treatment processes ((Steam Explosion (SE), Microbial Fermentation (MF) and Mechanical Grinding (MG)) intended for producing sustainable bioplastic feedstock, using Life Cycle Assessment. A gate-to-gate analysis compared the processes per 1000 kg feather input across multiple impact categories, including GWP, Acidification Potential (AP), Eutrophication Potential (EP), Respiratory Inorganics, and Water Scarcity. The scope was expanded to cradle-to-gate to include upstream farming impacts and compare results with conventional plastics. Gate-to-gate results showed MG had the lowest impacts for GWP (475 kg CO 2 eq.), AP (0.65 kg SO 2 eq.), EP (0.08 kg Phosphate eq.), and Respiratory Inorganics, driven by lower energy use. However, MG showed the highest Water Scarcity (7787 m3 world eq.) due to feather washing. MF exhibited the highest GWP (2035 kg CO 2 eq.) and Respiratory Inorganics, while SE showed the highest AP (1.25 kg SO 2 eq.). Cradle-to-gate, MG and SE offered significant GWP advantages over conventional plastics like PP, LDPE, and HDPE (up to 59% and 27% lower GWP, respectively). Similarly, MG and SE demonstrated lower AP (up to 56% and 48% lower, respectively) compared to these plastics. However, feather routes showed higher EP when upstream farming impacts were included. In conclusion, MG is the most favourable process regarding climate impact, though its water use is significant. SE provides a balanced alternative. Valorising feather waste offers environmental benefits over conventional plastics, but optimising energy efficiency and water consumption is crucial for enhancing the sustainability of these technologies.