Black soldier fly larvae (BSFL) reveal extraordinary efficiency in converting organic wastes into proteins and oils. Circular economy, food security and sustainable development.
Two very recent scientific reviews highlight the potential of this insect species and the versatility of using larvae and frass in feed and fertilizer production. Pending approval of larvae as novel food (1,2).
1) Background. The larvae of black soldier fly
1.1) Biodigester par excellence
The black soldier fly(Hermetia illucens) is an insect native to Central America, different from the musca domestica. And it is one of the very few alien (i.e., non-native) insect species that is possible to breed in the EU. Interest in it has stood out over the past decade because its larva is a biodigester par excellence.
In fact, BSFL(black soldier fly larvae) is capable of converting organic waste-including plant and animal by-products (including manure)-into raw materials for animal feed, fertilizer, biodiesel, and cosmetics. And in the future, subject to compliance with special specifications to ensure food safety, larvae may also be approved as novel foods (3,4).
1.2) Bioconversion, values and yields
Natural bioconversion of organic wastes by black soldier fly larvae (BSFL) has twofold significance:
– cheap. Scraps that include food waste, converted in a short time with minimal consumption of resources (soil, water, energy), can be reused in production chains,
– environmental. Insects can remove pollutants and contaminants (e.g., mycotoxins, pathogenic bacteria), thus contributing to the remediation of ecosystems.
The conversion yields of black soldier fly larvae are phenomenal, as it can virtually recycle up to 85 percent of the ingested biomass. With an average yield of 800 g (up to 1,024 g) of larval biomass from 4 kg of waste, depending on the nutritional properties (protein and carbohydrates) of the waste (substrate). To which is added the frass.
2) Black soldier fly larvae, BSFL. Agricultural and industrial applications
Feeds are now the application of greatest interest for black soldier fly larvae (BSFL). Dried larvae can be used as is, in whole form, or in oil or powder form. Their richness in protein and essential amino acids (except for methionine) far exceeds conventional mangins. In amounts that vary according to the substrate (waste) fed to the larvae.
Black soldier fly larvae oil has a distinctive lipid profile and composition that allow for several uses:
– skin care cosmetics,
– dietary supplements and drugs, thanks to the valuable chitosan with chelating function,
– Biopolymers and bioplastics material,
– biodiesel. In accordance with UNI EN 14214. With significant advantages over unsustainable palm oil, as it requires far less soil and water, as well as short time frames.
3) BSFL’s Frass
3.1) Biofertilizer with biostimulant properties.
Frass is a compost obtained from insect droppings, spent substrate and chitin residues produced by different molts. It can be used as a biofertilizer in agriculture to enrich the soil with organic matter with biostimulant actions (disease defense, rhizosphere stimulation and phytohormone production).
The reduction of waste in frass depends on its composition. The best results were observed in waste blends, rather than in individual streams. The conversion efficiency varies between 15 and 50 percent, depending on the substrate. Some trials have also been done for its use in aquaculture feeds (e.g., tilapia, sturgeon), with excellent results on improving health status and quality parameters.
3.2) Production Requirements
Reg. EU no. 142/2011 provided provisions on the production and agricultural use of frass, which must be heat treated at 70°C for 60 minutes.
Stabilization treatments (e.g., thermophilic composting, vermicomposting) are useful in improving the safety and efficiency of frass by balancing its microbiota and reducing any phytotoxicity profiles that might inhibit its bio-fertilizing function.
The best results on several crops were found with the use of frass (rich in phosphorus, potassium, micronutrients) not in purity but in combination with other fertilizers that provide nitrogen.
4) Hermetia illucens, nutritional properties.
4.1) Nutritional values
The nutritional values of Hermetia illucens larvae vary depending on three factors:
– substrate. If the waste used to feed the larvae is deficient in protein, it can be supplemented with protein by-products (e.g., from fishing, aquaculture and fish industry),
– temperature. It is recommended that breeding farms be established close to other production facilities in order to take advantage of their heat (through heat exchangers) and promote ideal growth of black soldier fly larvae at 25-30°C,
– transformation process. Spray-drying (pulverization) is a short process that results in higher concentrations of protein and fiber, with lower levels of saturated fat. A higher concentration of lipids, saturated fats especially, and minerals is achieved in the oven. The vitamin profiles are very similar, with richness in vitamins B1, B2 and C. (6)
4.2) Nucleotides, peptides and proteins
Nucleotides-that is, the molecular units that make up the nucleic acids DNA and RNA, which are used as stimulants in aquaculture-are present in black soldier fly larvae at levels equivalent to those in fishmeal.
Enzymatic degradation of proteins from black soldier fly larvae yielded 78 peptides and 57 proteins with high antioxidant capacity, with important potential in the food, cosmetic and pharmaceutical/medical sectors. (7)
Among other things, this process made it possible to identify the (few) allergenic peptides and selectively remove them. Thus increasing the safety of the black soldier fly for food use. (7)
5) Genotyping
Hermetia illucens
is a species native to the Americas (central zone), currently cosmopolitan as a result of its spread in different tropical, subtropical and temperate belts. Commercial and research interest has since stimulated its dissemination and exchange on a planetary level. However, this phenomenon poses a risk to its genetic integrity, as it does for many other species subject to wide distribution.
A mtDNA COI barcode was made for the specific purpose of characterizing the different populations and races of black soldier fly, also to have confirmation that the species is indeed Hermetia illucens and to keep a check on accidental hybridization. It is therefore recommended that researchers and business operators register the genetic barcodes of the black soldier fly larvae used (at a very low cost, moreover). DNA and biological samples should also ideally be preserved for future screening, with identification of nuclear markers. (8)
5) Black soldier fly larvae. European, Euro-Mediterranean and Italian research.
5.1) Horizon 2020, Horizon Europe
Horizon 2020
and Horizon Europe, successive European research programs in recent years and still ongoing, have devoted primary attention to the study of insects as sustainable sources of protein, as noted. From a food security and nutritional security perspective. (9)
The EcoeFISHent project – in Horizon 2020, under the scientific coordination of the University of Genoa – also aspires to enhance waste from fishing, aquaculture and fish industry by rearing black soldier fly larvae. In view of their use as bio-fuel, ingredient in cosmetics and bioplastics, bio-fertilizer.
5.2) FIRST, EIP-Agri and research in Italy.
Several universities in Italy have followed and/or are following projects on black soldier fly larvae. Of particular note are:
– University of Messina. The Hermetia project aimed to promote and incentivize the ability of black soldier fly larvae to reduce waste and increase the availability of alternative protein sources, in addition to the various ‘side’ products that can be derived, (10)
– University of Pisa. FEDKITO is a project co-funded by PRIMA, Partnership for Research and Innovation in the Mediterranean Area. With the goal of creating sustainable packaging, using chitosan (from chitin extracted from BSFL) to extend the shelf-life of various food products (e.g., fruits, vegetables, cheese), (11)
– University of Basilicata. A project under theAgricultural European Innovation Partnership (EIP-AGRI) program aimed to promote the use of black soldier fly larvae to dispose of nitrogen that comes from effluent in beef cattle farming and reintegrate its outputs back into the production cycle. (12)
6) Interim Conclusions
Roe Gutman – researcher who since 2019 has been coordinating a project aimed at producing proteins from black soldier fly larvae for food and feed use in aquaculture, at MIGAL (Galilee Research Institute, Israel) – shared with us a reflection on the role of this insect as a game changer In the agribusiness supply chain.
The ability of black soldier fly larvae to convert organic waste into protein, nutrients and micronutrients is a miracle of nature. Its breeding-at relatively low cost and minimal environmental footprint-can fulfill a primary need for food security and contribute to farmers’ income.
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) Siddiqui et al. (2022). Black soldier fly larvae (BSFL) and their affinity for organic waste processing. Waste Management 140:1-13, https://doi.org/10.1016/j.wasman.2021.12.044
(2) Guidini Lopes et al. (2022) Frass derived from black soldier fly larvae treatment of biodegradable wastes. A critical review and future perspectives. Waste Management 142:65-76, https://doi.org/10.1016/j.wasman.2022.02.007
(3) An EFSA opinion on the novel food application for Hermetia illucens submitted on 1/28/19 by Enorm Bifactory A/S (DK) is expected on 9/27/22. V. Dario Dongo. Insects on the table, Novel Food approvals in EU. The state of the art. GIFT (Great Italian Food Trade). 13.2.22, https://www.greatitalianfoodtrade.it/innovazione/insetti-a-tavola-autorizzazioni-novel-food-in-ue-lo-stato-dell-arte
(4) Leah W. Bessa, Elsje Pieterse, Louwrens C. Hoffman et al. (2021). Food Safety of Consuming Black Soldier Fly (Hermetia illucens) Larvae: Microbial, Heavy Metal and Cross-Reactive Allergen Risks. Foods. 2021 Aug; 10(8): 1934. doi: 10.3390/foods10081934
(5) Regulation (EU) no. 142/2011, laying down implementing provisions for reg. EC 1069/2009 laying down health rules concerning animal by-products and derived products not intended for human consumption. Text updated as of 3/28/22 on Europa-Lex, https://bit.ly/3rbQtcA
(6) Zulkifli et al. (2022) Nutritional value of black soldier fly (Hermetia illucens) larvae processed by different methods. PLoS ONE 17(2):e0263924, https://doi.org/10.1371/journal.pone.0263924
(7) Lu et al. (2022) Probing the antioxidant activity of functional proteins and bioactive peptides in Hermetia illucens larvae fed with food wastes . Scientific Reports 12:2799, https://doi.org/10.1038/s41598-022-06668-9
(8) Ståhls et al. (2020) The puzzling mitochondrial phylogeography of the black soldier fly (Hermetia illucens), the commercially most important insect protein species. BMC Evolutionary Biology 20:60, https://doi.org/10.1186/s12862-020-01627-2
(9) Dario Dongo, Andrea Adelmo Della Penna. Protein for the future, novel food. Challenges and opportunities in EU. FARE(Food and Agriculture Requirements). 12/15/21, https://www.foodagriculturerequirements.com/archivio-notizie/proteine-per-il-futuro-novel-food-sfide-e-opportunità-in-ue
(10) V. https://www. progettohermetia.it/
(11) SEE https://fedkito.agr.unipi.it/
(12) EIP-AGRI. Livestock manure valorization by innovative technology based on the use of the bioconverting insect Hermetia illucens. https://ec.europa.eu/eip/agriculture/en/find-connect/projects/valorizzazione-dei-reflui-zootecnici-mediante