From Soy Waste to Bioplastics: Industrial Proof of Concept

Abstract

The global plastic waste problem is pushing for the development of sustainable alternatives, encouraged by stringent regulations combined with increased environmental consciousness. In response, this study presents an industrial-scale proof of concept to produce self-standing, transparent, and flexible bioplastic films, offering a possible solution to plastic pollution and resource valorization. We achieve this by combining amyloid fibrils self-assembled from food waste with methylcellulose and glycerol. Specifically, soy whey and okara, two pivotal protein-rich byproducts of tofu manufacturing, emerge as sustainable and versatile precursors for amyloid fibril formation and bioplastic development. An exhaustive industrial-scale feasibility study involving the transformation of 500 L of soy whey into ∼1 km (27 kg) of bioplastic films underscores the potential of this technology. To extend the practicality of our approach, we further processed a running kilometer of film at the industrial scale into transparent windows for paper-based packaging. The mechanical properties and the water interactions of the novel film are tested and compared with those of commercially used plastic films. By pioneering the large-scale production of biodegradable bioplastics sourced from food byproducts, this work not only simultaneously addresses the dual challenges of plastic pollution and food waste but also practically demonstrates the feasibility of biopolymeric building block valorization for the development of sustainable materials in real-world scenarios.

Proteins for Applied and Functional Materials

“…have developed a biobased film solely based on natural ingredients, i.e., soy protein and okara pulp, which were successfully produced into large-scale packaging films (∼1km). The most significant sustainability indicator was not only the reduction of fossil plastic use in single-use applications such as food packaging, but also that the raw materials used are obtained as byproducts of the tofu production . The achievements in replacing plastics in food packaging with protein-based materials are also demonstrated by Na et al, who have developed antimicrobial films based on BSA protein and chitosan and were concept-proofed by increasing the life-span of strawberries from 2 to 8 days …”