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

在全球范围内，农业每年产生1400亿吨生物质废弃物，在能源和原材料方面相当于500亿吨原油（UNEP\_2009）。作物残余物包括生物质中不可食用的部分，如空豆荚、叶子和茎。作物收获后，大量的作物残余物被留在地里，然后被犁回土壤中，以增加有机质含量，作为天然肥料。不需要施肥的豆科作物残渣废料也可以用作动物饲料或（最后一种手段）作为废物处理（通过焚烧或填埋）。然而，人们越来越感兴趣的是，通过提取蛋白质等营养物质，使不需要施肥的豆科作物残留物增值的潜力（Tassoni\_et\_al\_2020）。英国豆类市场以蚕豆（主要用于动物饲料）和豌豆（主要用于人类消费）为主，作物产量（2017年）分别为78万吨和16万吨（LegValue\_2019）。豆类和豌豆通常在田间收获并去壳。由于豆类作物残留物占作物总生物量的45% (Amalfitano\_et\_al\_2018)，我们估计英国蚕豆生产目前每年产生超过63.8万吨的作物残留物。蚕豆和豌豆作物残茬的蛋白质含量估计分别为c13%（Karlsson\_et\_al\_2015）和c18%(Tassoni\_et\_al\_2020)；因此，我们估计，英国蚕豆和豌豆作物残留物的增值理论上可以提供100,000吨/年的植物蛋白。据估计，整个欧洲每年产生300万吨豆类废物（LEGUVAL\_2016），每年可能提供45万吨植物蛋白。Xampla的目标是使这种植物蛋白增值，以生产一种新型的创新高性能材料，超分子工程蛋白（SEP），它可以用作微塑料和一次性塑料的生物基/可生物降解材料替代品。作为示范，我们将开发生物基/可生物降解的SEP种子包衣，以替代传统的不可生物降解的化石燃料种子包衣。种子包衣是一个小批量但高价值的市场；然而，它们是一个理想的主要市场，因为农用化学品供应商正在积极寻找可持续的可生物降解解决方案，以满足拟议的欧盟禁令（到2026年），禁止故意添加微塑料，包括种子包皮（ECHA\_2020）。二级市场包括取代现有全球市场上的传统塑料，如食品包装薄膜/涂料，同时也创造新的市场机会，包括使用SEP材料作为新鲜农产品的可食用涂层，以延长保质期并减少农场后食品浪费。帮助英国农民和农业部门从COVID-19中持续恢复；实现清洁增长和净零增长。

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.