Engineering insects for novel food/feed and waste management

昆虫在低碳食品生产方面具有巨大潜力，如果使用废物作为原料，也可以进行废物管理。该应用程序解决了工程生物学的两个关键需求：(i)食品和饲料使用的高质量营养物质（如蛋白质、脂质）的高效、低碳生产的需求-食品系统（主要）；（ii）有机废物的生态友好回收的需求-环境解决方案。昆虫的大规模饲养为这些问题提供了一个有吸引力的解决方案。昆虫是高效的饲料转化者，比牲畜甚至家禽都要高效得多，同时需要的土地更少，温室气体排放量也低得多。直接大规模用于人类仍然是一个市场挑战，但主要应用包括鱼和家禽饲料，以及宠物食品，已经有了。昆虫也能提供草籽和原料，从中可以提纯出高价值的产品，如几丁质。此外，一些昆虫可以在低价值有机废物上有效饲养，将各种输入物质转化为昆虫生物量。黑兵蝇（Hermetia illucens， BSF）——本提案的主题——可能是废物管理的典范，也是几种有吸引力的食物和饲料使用方案之一。这两种应用是重叠的，但又截然不同——不同的地区对输入材料有不同的规则，但是，例如，在污水中饲养的昆虫通常不能直接用作饲料，尽管仍然可以从昆虫生物量中纯化出有价值的副产品。生物流化床因其将营养贫乏的有机废物饲料转化为适合动物食用的体重和植物肥料的特殊能力而越来越受到国际关注。由于BSF幼虫作为动物饲料的使用处于相对早期的阶段，研究自然集中在测试其可作为食物的底物范围和优化大规模饲养方法以提高生物转化效率。然而，人们在选择性育种和大规模饲养方面所能做的只有这么多——尽管有最好的遗传和饲养方案，但基本的生物学限制仍将适用。BSF作为动物饲料的一些明显局限性包括：与家蝇蛆、粉虫和成年蟋蟀相比，BSF的多不饱和脂肪酸含量较低，木质纤维素底物转化效率低，对滴滴涕和拟除虫菊酯（可能存在于作物残留物中的杀虫剂）敏感。用传统育种方法解决这些问题极具挑战性，但有可能采用工程方法。简而言之，黑兵蝇具有巨大的潜力，但野生型昆虫并非适用于所有应用——本提案旨在为黑兵蝇的合理工程开发一个平台和原型（Hermetia illucens， BSF）。这具有广泛的潜在应用，我们开发了两个作为实际例子-通过允许加强使用被杀虫剂污染的废物来扩大它可以利用的投入材料的范围，并调整昆虫的组成，这里的脂肪酸组成，以增加收获产品的价值。未来，这样的平台可以为广泛的增强特性提供基础，例如消化目前难以消化的源材料，可能是木质纤维素废物，如谷物残茬，甚至塑料。已知节肢动物具有合适的酶和途径；一个工程平台将允许特定的理想特性转移到一个可适应的底盘有机体，如BSF。

Insects have enormous potential for low-carbon food production, also waste-management if using waste as feedstock. This application addresses engineering biology to address two critical needs - (i) the need for efficient, low-carbon production of high-quality nutrients (e.g. protein, lipid) for food and feed use - food systems (primary), and (ii) the need for eco-friendly recycling of organic waste - environmental solutions. Insect mass-rearing represents an attractive solution for each of these. Insects are highly efficient feed converters, much more so than livestock or even poultry, while also needing less land and with far lower greenhouse gas emissions. Direct use for humans at scale remains a marketing challenge, but major applications including fish and poultry feed, and pet food, are already available. Insects also provide frass, and material from which high-value products such as chitin may be purified. Additionally, some insects can be reared effectively on low-value organic waste, converting a wide range of input material into insect biomass. Black soldier fly (Hermetia illucens, BSF) - the subject of this proposal - is perhaps the exemplar for waste management, and one of several attractive options for food and feed use. These two applications are overlapping but distinct - different territories have different rules about input material, but insects reared on sewage, for example, typically cannot be used directly for feed, though valuable by-products may still be purified from the insect biomass.BSF has increasingly garnered international attention for its exceptional ability to bio-convert nutrient-poor organic waste feed into body mass suitable for animal consumption and fertilisers for plants. As the use of BSF larvae (BSFL) as animal feed is at a relatively early stage, research has naturally focused on testing the range of substrates it can utilise as food and optimising mass rearing methods for bioconversion efficiency. However, there is only so much one can do with selective breeding and mass rearing - fundamental biological limitations will still apply despite having the best genetics and rearing protocol. Some obvious limitations of BSF as animal feed include: lower polyunsaturated fatty acid content compared to housefly maggots, mealworms, and adult crickets, inefficient conversion of lignocellulosic substrates, and susceptibility to DDT and pyrethroids, insecticides which may be present in crop residues. These would be extremely challenging to address by conventional breeding, but potentially amenable to an engineering approach.In short, BSF has enormous potential but wild-type insects are not ideal for all applications - this proposal aims to develop a platform and prototypes for rational engineering of black soldier fly (Hermetia illucens, BSF). This has a wide range of potential applications, of which we develop two as practical examples - to expand the range of input material it can utilise by allowing enhanced use of insecticide-contaminated waste, and to adjust the composition, here fatty acid composition, of the insect to add value to harvested product. In future, such a platform could provide a basis for a wide range of enhanced traits, for example digestion of currently indigestible source material, perhaps lignocellulosic waste such as cereal stubble, or even plastics. Arthropods with suitable enzymes and pathways are known; an engineering platform would allow specific desirable traits to be transferred to an amenable chassis organism such as BSF.