Engineering insects for novel food/feed and waste management

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.