Upcycling Brewers' Spent Grain Into High‐Performance Protein Nanofibers for Sustainable Non‐Woven Textiles

ABSTRACT Brewers’ spent grain (BSG), a major by‐product of the brewing industry, remains an underexploited source of protein suitable for the development of sustainable textile materials. This study reports the extraction and electrospinning of hordein, a prolamin protein derived from BSG, to produce nanofibers with properties relevant to advanced textile applications. Glycerol diglycidyl ether (GDE) was employed as a bifunctional cross‐linker to enhance the mechanical integrity and aqueous stability of the fibers. GDE cross‐linking, combined with heat treatment, resulted in substantial improvements in tensile strength, elongation, thermal stability, and water resistance. Hordein‐based fibers displayed markedly higher flexibility and elongation than zein‐based controls, consistent with a more deformable prolamin network under tensile deformation. The incorporation of GDE also increased surface hydrophobicity, with contact angles exceeding 120° after heat treatment, indicating strong resistance to water penetration: an essential requirement for functional textile performance. These findings demonstrate the viability of upcycling BSG into high‐performance, biodegradable nanofibers and underscore the potential of protein‐based alternatives for next‐generation sustainable textiles, thereby supporting the transition toward a more circular and environmentally responsible textile industry.