Trash to treasure: advancing resource efficiency using waste-derived fillers as sustainable reinforcing agents in bioplastics

The escalating environmental challenges posed by different waste sources, including agricultural residues and industrial byproducts, necessitate innovative solutions for waste utilization. Converting waste into valuable resources offers a sustainable approach to mitigating pollution and conserving natural resources. Driven by the urgent need for eco-friendly packaging solutions, this review explores the potential of waste-generated fillers to enhance bioplastic performance. The integration of waste-derived fillers, including nanofillers, into bioplastic matrices significantly improves the mechanical, thermal, and barrier properties, promoting the principles of circular economy and industrial symbiosis. This approach also contributes significantly to reducing carbon footprints by minimizing waste and promoting the reuse of byproducts for sustainable bioplastic production. Addressing the growing concern over the potential toxicity of commercial fillers, specifically metal and metal oxide-based nanofillers, bio-based fillers have emerged as a promising alternative, offering a safer and more eco-friendly solution. An in-depth analysis of recent advancements in processing, production, utilization, challenges, and future prospects would serve as a valuable guide for researchers, industry professionals, and policymakers. The key findings of this review emphasize the necessity of modifying or pre-treating waste fillers to optimize the properties of bioplastic composites. According to the literature, corn processing residues, coffee waste, eggshell waste, and sugarcane bagasse-based fillers are particularly notable among the most studied materials for green composites. Polylactic acid is the most commonly used biopolymer for experimentation with waste-derived fillers. This review underscores the transformative potential of waste valorization in enhancing bioplastic performance, stressing the need for continued research, innovation, and supportive policies to drive sustainable development in this field.