ABSTRACT: The increasing demand, cost escalation and environmental impact of raw materials for industrial chemicals, materials, and energy production impel the development of sustainable strategies for resource utilization. Such sustainable resource demand spurred investigation for the utilization of agricultural and forestry wastes and by-products. The emergence of bovine spongiform encephalopathy reduced most of the traditional uses of rendered animal meals such as blood meal, meat, and bone meal as animal feed, effectively making it an industrial waste. The purpose of this research was to valorize these protein rich rendering wastes for the use of polymeric materials. The proteinaceous wastes were first hydrolyzed in accordance with approved government protocols, followed by optimization of protein fragments recovery. The level of cleavage of recovered protein fragments and other characteristics as applied to polymeric materials were evaluated. The recovered and characterized protein hydrolyzates were then modified via various chemical and polymer processing approaches, including reactive extrusion and chemical crosslinking to develop plastic films and sheets. The plastics made as such exhibited promising thermal and mechanical performance. Continuing based on these results, composites materials were developed using the protein – synthetic polymer hybrid plastics as matrices and reinforcing with natural fibers and fiberglass. Results of the study showed that the resulting composites exhibited promising flexural, tensile and impact strength; despite the relatively poor moisture resistance. In another platform, an adhesive for engineered wood composites such as oriented strand board and plywood was developed from the hydrolyzed protein. In summary, this study has shown that using the knowledge of polymer chemistry and engineering, an otherwise waste proteinaceous material can be valorized into a feedstock that can be used for a range of useful polymeric materials including plastic sheets, adhesives, and composites. This approach avoids the cost of landfilling, perceived competition of biomass feedstock with food production while at the same time producing an alternative income source for the agriculture/forestry industries.
Bio-sketch: Dr. Tiz Mekonnen earned a BSc (Applied Physics and Material Science), an MSc in Chemical Engineering from Addis Ababa University, and a PhD in Bioresource Engineering (2013) from the University of Alberta. He then joined the Biomaterials Discovery and Development Center of the University of Guelph as a postdoctoral fellow. Tiz’s PhD and Postdoctoral fellowship research work entailed processing - structure and property correlation of biopolymers and biopolymer–synthetic polymer hybrid materials for various industrial applications including films, (nano) composites and adhesives. He has also worked for TerraVerdae BioWorks Inc. (TVB) as a Polymer Processing and Application Development Scientist, and conducted researches on polymeric films, coatings, biodegradable micro-plastics as cosmetic additives, three-dimensional (3D) printing filaments, and nanocomposites. This has led to his current role within E.I. DuPont as a polymer engineering scientist, where his work is focused on optimization of performance and application development of newly developed polymers. Dr. Mekonnen has published 14 peer-reviewed journal articles, one book chapter, and 3 inventions filed for a patent.