From waste to compostable packaging: The environmental end-of-life impact of modified cellulosic films

Industrialisation of manufacturing has dramatically reduced the cost of products for consumers leading to the creation of a throw-away society in which we “take-make-dispose”. Over the next couple of decades more than a billion tonnes of oil-based plastic will be dumped into landfill and seep into our oceans. Many synthetic plastics do not biodegrade and will remain in our environment practically indefinitely. This plastic waste not only damages our environment, but also enters our food chain.

This project will improve understanding of the biogeochemical cycle in a new range of packaging materials. These are coated films that are biodegradable and formed from sustainable sources (such as plant/crop waste). These films can replace current conventional fossil-fuel based/plastic packaging materials. To verify their suitability as biodegradable non-toxic material, the student will evaluate how their disposal affects plant growth, the soil structure and the animal ecosystems. The project brings together academia with industry, Futamura Chemicals UK Limited, plant biologists and experts in animal nutrition to create a new partnership that bridge the efforts invested in the generation of natural and compostable flexible packaging with an understanding of their environmental and physiological effects for a truly circular economy. During the project, cellulosic films will be made using crop wastes such as tomato leaves and stalks, brewer’s grains and hemp residuals at the laboratory of the industrial partner. Solvent coating, required for barrier properties and heat sealability, will be substituted by a compostable aqueous coating technology identified by Futamura. The specific goal in this project is to identify the environmental end-of-life impact of these cellulosic films obtained from crop wastes, specifically focusing on their compostability (biodegradation in soils and aquatic systems) and suitability for plant growth and the cycling of matter in soil and water.

The objectives are:

O1 Determine the effect of the current, agricultural waste films and resin coatings on soil properties;

O2 Determine the effect of the current, agricultural waste films and new resin coatings on plant germination and association with mutualistic fungi and bacteria;

O3 Determine the microbial mediated degradability of the current agricultural waste films and new resin coatings in soil and in sea or fresh water;

O4 Determine the digestibility of the cellulosic films when consumed by animals (terrestrial and marine);

O5 Determine the effect of the cellulosic films on auto- and allo-enzymatic digestive processes in animals;

O6 Collaborate with industry to deliver the optimum combinations of base films and coatings to minimize the environmental end-of-life impact of the material.

At the end of the project, we will deliver crucial information on the environmental impact of using these films in comparison to more traditional packaging material. This knowledge can be used to influence the public and policy makers and create a sustainable end-of-life solution that reduce plastic pollution. The successful candidate will have access to our extensive world-leading laboratories within the Faculty of Biological Sciences at Leeds and benefit from interactions with an industrial global leader in cellulose materials. The lead supervisor (Yoselin Benitez-Alfonso) is currently a UKRI Future Leader Fellow which focuses on cell walls and plant environmental responses. Together with Co-supervisor Henry Greathead, this PhD exploits the knowledge in plant cell walls and animal digestion in the development of biodegradable biomaterials.