A predictive tool for bio-based chemical extraction

This project will address a major challenge in the development of new products such as cancer treatment drugs and prebiotics by enabling the scalable extraction of "hairy" pectins from food processing wastes (more correctly termed co-products) for the first time. Food processing co-products are currently used for low value applications such as animal feed or sent to landfill, which results in the third largest contribution to global greenhouse gas emissions. Development of these new products from food processing wastes could therefore improve health, add value to agricultural products and reduce greenhouse gas emissions.

Current pectin extraction methods are unsuitable for hairy pectin extraction as the acid that is used as a solvent in the process damages the hairy pectin structures, and therefore a new method must be developed. Using microwaves as the heating source during pectin extraction may lead to the ability to extract hairy pectins at scale using milder solvents such as water. However, the quality and yield of the pectin extracted is a complex function of the source plant material, the solvent used, temperature and time as well as heating method, and there is currently very little fundamental understanding of the influence of all of these factors or their interdependence. To address this challenge, the work proposed will develop a tool to predict hairy pectin extraction yield and composition as a function of the feedstock, extraction conditions and heating method (microwave or conventional heating). This tool will be used to select a suitable UK food industry co-product for hairy pectin extraction and propose a design for a novel extraction process. A preliminary assessment of the operating and capital costs, the environmental footprint and the safety issues associated with the proposed design will be made. By the end of the project, a consortium of industrial and academic partners will be assembled for the next stage of development, which will be to build a rig capable of producing kilogram-quantities of hairy pectins and test them in human trials to assess their potential uses (e.g in cancer treatment or as prebiotics to improve gut health). Human trials are currently not possible as sufficient quantities of hairy pectin cannot be extracted, and this project could therefore lead to significant impacts on health and make a major contribution to the effort to bring these products to market.

The modelling tool to be developed is intended to be applicable in the future to other biorefinery unit operations. Reducing reliance on petrochemicals by developing technologies to generate the pharmaceuticals, chemicals and fuels we need from biological sources, waste products in particular, is a priority of many researchers and companies worldwide. The fundamental understanding of biomass processing that will come out of this project will support this goal, enabling the production of a wide range of beneficial biochemicals using sustainable processes.

The key impacts will be the health benefits resulting from the new products developed, the valorisation of waste streams, and advancement of biomass processing technology and productivity.

Impact will arise from the potential health benefits of the products that this work aims to develop. There is in vitro evidence that certain hairy pectin-derived products have potential use in cancer treatment and to have prebiotic properties. Human volunteer trials are required to assess these potential beneficial (and valuable) uses further, and this will require a kilogram-scale production technique, which, critically, the proposed work will enable. The proposed work will enable new production processes to be developed, resulting in increased productivity and job creation in the agri-food sector and potentially pharmaceutical and chemicals sectors, etc. depending on the new products created. The potential feedstocks for the process include food industry co-product (or waste) streams that are currently used for low value applications such as anaerobic digestion, composting and animal feed (animal feed sales prices in the UK are ~£10-£50/tonne), or disposed of at a cost (current UK landfill tax rate is £86/tonne). Landfilling of food processing waste results in the third largest contribution to greenhouse gases worldwide, and fruit processing wastes account for 6% of global greenhouse gas emissions. The new processes developed have the potential to be portable, and as such could contribute to global sustainable development goals by servicing areas with little infrastructure and widely distributed waste products. The new products and processes developed would therefore improve health, generate wealth and improve the sustainability of food processing operations in the UK and elsewhere.

Pectins are not the only potential products that can be extracted from biomass via solvent extraction, and it is intended that the tool developed for this project will provide a framework that can be expanded in the future to be applicable to a wide range of processes. For example, there are other cell wall components such as arabinoxylans, which are present in co-streams from industries such as brewing and distillery and are being investigated for use as novel food ingredients and prebiotics. There are a wide range of intracellular components such as polyphenolic compounds like flavonoids (e.g. quercetin in onion), which are known to provide health benefits and can be used as natural food colours. The tool could be adapted for the optimisation and scale-up of other non-solvent based extraction techniques such as solvent-free microwave extraction, a technique that is widely applied to essential oil extraction and currently only exists at small scale (up to 1.5g oil extracted per batch). The global market for essential oils was around £4.4bn in 2014 and is projected to double by 2020, with the UK being one of the largest exporters to Europe, the largest global market.

Beyond extraction, the tool could be applied to other biorefinery unit operations, supporting the UK's bioeconomy, which is ranked 1st globally on Field Weighted Citation Impact in research and innovation. It could be applied to the pretreatment and upgrading of lignocellulosic materials and also to biomass pyrolysis processes. In particular, microwave pretreatment and pyrolysis are known to result in unique biomass breakdown products that could lead to the production of platform chemicals via new routes; the tool could help to understand and exploit these microwave-enhanced effects.

The tool developed here will require further development to meet all of these challenges, but it will provide a framework upon which to build. It is clear that if its potential impact is fully realised, the proposed work could contribute to the development of many new biochemical production processes whilst reducing the environmental footprint of existing industry operations.