Valorization of corn stover into biodegradable biocomposites: characterization, prototype design, and upcycling into bacterial nanocellulose

The presented study explored the development and end-of-life evaluation of novel biocomposite materials - termed SferiCorn (Sferi) - developed using ground corn stover (CS) in the form of short fibers and three biopolymer matrices: starch (Sferi R), alginate (Sferi S), and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBH) (Sferi BioTP). The composites were characterized in terms of thermal behavior (DSC/TGA), swelling properties, structure (FTIR), morphology (SEM), and degradation under composting, hydrolytic, and enzymatic conditions. Results showed that matrix composition strongly influenced material properties, but also guided the end-of-life options with starch-based composites degrading rapidly under composting and aqueous conditions, alginate-based composites exhibiting moderate degradability, and PHBH-based composites showing increased stability. Sferi BioTP composite, additive free, was chosen for product prototyping due to its favorable mechanical properties. Developed coat-hanger served as proof-of-concept for a sustainable and scalable product design, eliminating synthetic additives while replacing conventional plastic and metal materials with a circular, bio-based alternative. Importantly, within a circular bio-economy framework, SferiCorn biocomposites were upcycled into a new biopolymer, bacterial nanocellulose (BNC), as their hydrolysates supported markedly higher BNC yields than pure glucose media. This work demonstrated the valorization of agro-waste and the potential of using CS in application-specific biocomposites with tailorable end-of-life options. Three biocomposites were developed using CS with starch, alginate, PHBH Properties and degradation were tuned by polymer selection CS- PHBH (Sferi BioTP) proved suitable for development of a coat hanger prototype Biocomposite hydrolysates enabled BNC production, closing the multicircular loop