NOVEL SUSTAINABLE MANUFACTURING TECHNOLOGIES FOR EFFICIENT UTILISATION OF AGRICULTURAL WASTE STREAMS IN A CIRCULAR ECONOMY

The chemical and pharmaceutical industries are currently reliant on petrochemical derived intermediates for the synthesis of a wide range of valuable chemicals, materials and medicines. Decreasing petrochemical reserves, and concerns over increasing cost and greenhouse gas emissions, are now driving the search for renewable and environmentally friendly sources of these critically needed compounds.

This project aims to establish a range of new manufacturing technologies for efficient conversion of biomass in agricultural waste streams into sustainable sources of these valuable chemical intermediates. The UK Committee on Climate Change (2018) has highlighted the importance of the efficient use of agricultural biomass in tackling climate change. The work undertaken in this project will contribute to this effort and help the UK government achieve its stated target of 'net-zero emissions' by 2050.

The new approaches will be exemplified using UK-sourced Sugar Beet Pulp (SBP) a renewable resource in which the UK is self-sufficient. Over 8 million tonnes of sugar beet is grown annually in the UK on over 3500 farms concentrated in East Anglia and the East Midlands. After harvest, the beet is transported to a small number of advanced biorefineries to extract the main product; the sucrose we find in table sugar. SBP is the lignocellulosic material left after sucrose extraction. Currently it is dried (requiring energy input) and then sold as a low-value animal feed.

SBP is primarily composed of two, naturally occurring, biological polymers; cellulose and pectin. Efficient utilisation of this biomass waste stream demands that applications are found for both of these. This work will establish the use of the cellulose nanofibres for making antimicrobial coatings and 3D-printed scaffolds (in which cells can be cultured for tissue engineering and regenerative medicine applications). The pectin will be broken down into its two main components: L-arabinose and D-galacturonic acid. The L-arabinose can be used directly as a low-calorie sweetener to combat the growing problem of obesity. The D-galacturonic acid will be modified in order to allow formation of biodegradable polymers which have a wide range of applications. This new ability to convert SBP into a range of useful food, chemical and healthcare products is expected to bring significant social, economic and environmental benefits.

In conducting this research we will adopt a holistic approach to the design of integrated biorefineries in which these new technologies will be implemented. Computer-based modelling tools will be used to assess the efficiency of raw material, water and energy utilisation. Techno-Economic Analysis (TEA) and Life Cycle Analysis (LCA) approaches will be employed to identify the most cost-effective and environmentally benign product and process combinations for potential commercialisation. The results will be widely disseminated to facilitate public engagement with the research and ethical evaluation. In this way the work will support the UK in its transition to a low-carbon, bio-based circular economy.