Valorisation of plant-based waste agricultural biomass to produce circular biodegradable materials including seed coatings

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Globally, agriculture generates 140billion tonnes/year of biomass waste, equivalent in terms of energy and raw materials to c50billion tonnes of crude oil(UNEP\_2009). Crop residues comprise inedible parts of biomass, such as empty pods, leaves, and stems. Large amounts of crop residues are left on the field after crop harvest and ploughed back into the soil to increase the organic matter content, acting as a natural fertiliser. Leguminous crop residue waste not needed to fertilise the soil may also be used as animal feed or (last resort) disposed of as waste (via incineration or landfill). However, interest is growing in the potential to valorise leguminous crop residues not needed to fertilise the soil, by extracting nutrients such as proteins(Tassoni\_et\_al\_2020). The UK legume market is dominated by faba (broad) beans (mainly for animal feed) and field peas (mainly for human consumption), with respective crop production volumes(2017) of c780,000tonnes and c160,000tonnes(LegValue\_2019). Beans and peas are typically harvested and deshelled in the field. Since bean crop residues account for c45% of the total crop biomass (Amalfitano\_et\_al\_2018), we estimate that UK faba bean production currently creates over 638,000tonnes/year of crop residues. The protein contents of faba bean and pea crop residues have been estimated at c13%(Karlsson\_et\_al\_2015) and c18%(Tassoni\_et\_al\_2020), respectively; therefore, we estimate that valorisation of UK faba bean and pea crop residues could theoretically provide 100,000+ tonnes/year of plant protein. Across Europe, it is estimated that 3million tonnes of legume waste are produced each year(LEGUVAL\_2016), potentially providing c450,000tonnes/year of plant protein. Xampla's ambition is to valorise this plant protein to produce a new and innovative class of high-performance materials, Supramolecular Engineered Protein(SEP), which can be used as a bio-based/biodegradable material replacement for microplastics and single-use plastics. As a demonstrator, we will develop bio-based/biodegradable SEP seed coatings as a replacement for conventional non-biodegradable fossil fuel-based seed coatings. Seed coatings are a small-volume but high-value market; however, they make an ideal primary market, since agrochemical suppliers are actively looking for sustainable biodegradable solutions to meet the proposed EU ban(by 2026) on intentionally added microplastics including seed coatings(ECHA\_2020). Secondary markets include replacing conventional plastics in existing global markets such as food-packaging films/coatings, while also creating new market opportunities, including the use of SEP material as an edible coating for fresh produce to extend shelf-life and reduce post-farm gate food waste. Helping UK farmers and the agricultural sector recover sustainably from COVID-19; delivering on Clean Growth and net zero.