Upcycling of Livestock Industry Blood Waste into Bioplastics: Plasma Protein-Based Amyloid Fibrils

This study presents a novel approach to harnessing the underutilized resource of livestock blood plasma proteins to produce bioplastic films based on amyloid fibrils. Upon acidic heating, a 20-h incubation period resulted in mature, semiflexible fibrils with an average length of 0.65 μm and a persistence length of 261 nm. Characterization using Thioflavin T intensity, circular dichroism, and FTIR spectroscopy revealed a cross-β-sheet structure stabilized by hydrogen bonding. The integration of plasma protein amyloid fibrils with poly(vinyl alcohol) (PVA) or methyl cellulose (MC) yielded bioplastic films that exhibit smooth and homogeneous micromorphology, enhanced toughness, and water stability, with PVA-based films demonstrating an exceptional elongation of ∼300%, suitable for food packaging applications. Compared to petroleum-based plastics, plasma amyloid fibril-incorporated films demonstrated a superior sustainability footprint (∼92%). This work underscores the potential of plasma protein amyloid fibrils in bioplastic applications, aligning with the global imperative for eco-friendly waste management and a circular economy.