Black soldier fly (
Hermetia illucens) larvae (BSFL) can transform wastes to high-value and high-quality biomass. BSFL is a saprophytic insect, regarded as the “crown jewel” of insects for its inherent ability to convert organic waste and food processing byproducts into protein and lipid-rich biomass. It can achieve high rates of waste reduction, high degrees of feed-conversion efficiency to redirect substrate carbon into critical nutrients, yielding net CO
2 emission an order of magnitude lower than composting [
1]. BSFL of 1 kg quantity can be obtained with 1.4 kg of feed, compared to 2.3 kg and 3.8 kg feed for crickets and mealworms [
2]. It has minimum requirements for land and water, and a significant reduction of greenhouse gas emissions [
3–
5], but compared to other insects, producing BSFL may have relatively higher energy use [
6]. BSFL occupies a unique economic and environmental advantageous position, i.e. production cost is 30% lower than that for traditional proteins, and a production cycle of only 15–18 days per generation, and a 65% reduction in the carbon footprint [
7]. Thus, insect farming has been considered as an ideal tool to be utilized to establish a circular bioeconomy [
5,
8–
12]. BSFL biomass offers protein, lipids, micronutrients, chitin, and antimicrobial peptides, a proven ingredient for animal feed to replace fishmeal, with frass serving as a nutrient-rich biofertilizer. BSFL has been approved by many countries to be used to feed poultry, fish, and swine. Even though pathogen and antibiotic resistance gene loads can also be reduced during waste-to-larvae bioconversion, the BSFL may also bioaccumulate heavy metals or other harmful compounds. Biorefining of the larvae could be used to enrich the desirable components and remove harmful elements.
BSFL has emerged as a leading candidate for integrated waste-to-resource systems to address the global challenges of organic waste generation and rising protein demand and environmental pressure. The insect farming industry is expanding rapidly in Europe and the USA. The global BSF market was valued at $0.35 billion in 2024, and is expected to reach $5.60 billion by 2035 with a 29% growth rate during 2025–2035. This growth is mainly attributed to the increasing demand for protein meal from animal feed manufacturers and growing aquaculture industry, government support and approval for insects to be used in animal feed and pet food, and growing investment by the key players of the industry.
This review only highlights a few aspects of the published research, such as its composition, oil and protein extraction strategies and performance, feed quality and nutritional performance for a few animal species, using frass and biorefining co-products as biofertilizers, the potential to use BSFL oil in sustainable aviation fuel production, bioactive compounds and their demonstrated activities, and the need for comprehensive technoeconomic and life cycle analyses.
1 Publications and Academic Landscape
The number of research publications has grown exponentially in the past 10 years. A Scopus search using “black soldier fly” conducted on September 3, 2025, led to a total of 2568 documents from 2002 to 2026, and the trend is shown in Figure 1. The key observations of these publications are early stage (2014–2017), which is more focused on providing evidence and proof-of-concept that BSFL could thrive on diverse waste streams by evaluating the bioconversion rate (how much waste is reduced) and growth rate (how much biomass is produced). During the next stage (2017–2021), the research was more focused on optimizing rearing conditions, nutritional profiling, feeding performance and feed safety evaluations such as heavy metals and mycotoxin mitigation. More recently since 2021, more publications have emphasized processing to fractionate protein, oil, and chitin, using BSFL as a tool in the circular bioeconomy systems (CBS), industrial scaling, life cycle assessment (LCA), and techno-economic analysis (TEA), as well as system automation, and applications beyond feed, such as food ingredients, and even in pharmaceuticals. Since 2024, the growth rate has significantly slowed. This reflects an expected natural progression for a research field as it moves from initial discovery to a more focused and applied nature.
BSFL research is global as shown in Figure 2, but it is led by a few key hubs. In Europe, the Wageningen University (Netherlands) is the global leader. Germany, Italy, and Belgium also contribute significantly, all driven by EU policy supporting circular economy and alternative proteins. In Asia, China’s Huazhong Agricultural University has the highest volume of publications, where significant research efforts have been focused on waste management and feed. South Korea, Malaysia, and Thailand also contribute to the strong academic activities. In North America, publications from the USA, led by Texas A&M University, and Canada are more focused on biomass and waste reduction and feed quality evaluations. In the emerging critical region of Africa, such as Kenya, Ghana, and South Africa, research has been focused on using BSFL as small-scale and low-cost waste management tool to produce protein for broiler and aquaculture.
It is worth mentioning that during the “Insects to Feed the World” conference held in May 2018, in Wuhan China, about 40% of the presentations and posters were about BSFL [
13]. Tomberlin et al. [
14] made an appeal to scientists, policy makers, government officials, and food production representatives to create legal opportunities for this promising and sustainable resource to be explored and ultimately commercialized.
The BSFL research landscape over the last decade has shown independent academic fields of waste bioconversion, microbiomes and heavy metal and pathogen remediation, nutrition and feed safety, process engineering and biorefining, and now it is a major area of global research and systemic integration for commercialization. This is strongly driven by the needs for sustainable protein and waste upcycling. Figure 3 illustrates the main areas and percentages of the published works.
2 BSFL’s Macronutrient Composition
BSFL exhibits high feed conversion efficiency, and it can process a broad spectrum of organic materials, including food waste, agricultural byproducts, and even livestock manure. The larvae production environmental control and optimization have been thoroughly reviewed elsewhere, such as by Gold et al [
15]. Various factors can influence BSFL growth and compositional quality as reviewed by Iqbal et al. [
16], highlighting the importance of optimizing breeding systems and feed formulations. Even though this polyphagous insect can feed on all varieties of animal and plant-based organic matter, it is essential to apply mechanical crushing and heating treatment to improve BSFL digestion. In general, BSFL’s gut microbiota and enzymes can change to allow them to digest a variety of substrates. However, the survival rate, growth rate, and nutritional value of BSFL can be affected by extreme dietary nutrient imbalance, and environmental conditions such as extreme relative humidity and temperature. The commonly reported BSFL composition falls in the ranges shown in Table 1, along with their main influencing factors.
Lalander et al. [
17] studied effects of feedstock (8 urban organic wastes and two controls) on larvae development and process efficiency. Substrate properties, such as total organic matter and protein content affected waste-to-biomass conversion ratio, larvae development time and final product weight. BSFL was found to be versatile in their feedstock preferences, provided that the basic carbon and nitrogen are sufficient to support larvae development. This study reports that average crude protein content of the prepupae was 41.2% and it did not vary greatly among the prepupae reared on the 10 different substrates tested. In general, substrates containing higher concentrations of non-fiber carbohydrates yielded larvae with greater crude oil content. Mixing biowastes to similar protein and non-fiber carbohydrate contents can also significantly increase the performance and reduce the variability of BSFL in comparison to the treatment of individual wastes [
15]. Research findings in general indicate that the mineral content and fatty acid profile of BSFL are greatly dependent on the substrate, in contrast to their amino acid profile that shows a low variation. It is worth noting that the composition variation reported in the literature can partially be due to life stage and analytical methods used.
Larvae’s diet can significantly affect fat content and fatty acid composition, and the content of vitamins, carotenoids, and minerals [
18]. The amount and the fatty acid composition are highly variable and affected by both life stage and diet. BSFL fed diets containing fish oil or fish by-products accumulated both eicosapentanoic acid and docosahexaenoic acid. Even though fatty acid composition varied considerably from one stage to another, the quantity of lauric acid (C12:0) was consistently high through the entire life cycle of BSFL [
19]. The mineral content of black soldier fly larvae fed 16 different diets also varied greatly (0.8% to 8.3%). The mineralized exoskeleton of BSFL is the reason for these extreme variations as reported by Marangon et al. [
20]. BSFL meal can deliver substantial calcium and moderate phosphorus, in addition to essential amino acids, when used as feed [
1].
There are dynamic changes in protein and fat content throughout the entire life cycle (from egg to adults) of BSFL [
19]. A rapid increase in crude fat content was observed from the 4- to14-day larvae with its maximum level reaching 28.4% in dry mass, whereas the crude protein displayed a continuous decreasing trend in the same development phases with a minimum level of 38% at 12-day and a peak level of 46.2% at early pupa stage. Different growth stages can have varied chitin content, with an increased molecular weight and tighter chain packing of chitin at later life stage. Such enhanced chitin content and its greater crystallinity offer superior mechanical and barrier properties [
20]. Even though such chitin may offer application-specific properties such as used in packaging material, it may negatively impact protein extraction and its nutritional value.
The author’s research group has also compared lipid composition of adult flies with the larvae [
21], as shown in Table 2. BSFL (microwave dried) and adult flies (naturally died) have different lipid class composition profiles. Adult flies contained significant amounts of degraded lipids as shown by the high free fatty acid and partial acylglycerol contents, indicating the energy conversion from lipid reserve for larval metamorphosis as part of the natural biological process.
The author’s research team also compared the fatty acid profile of larvae and adult flies, as shown in Table 3. As expected, lauric acid (C12:0) is the predominant fatty acid in both samples followed by myristic (C14:0) and palmitic (C16:0) acids. The discovery of a range of iso- and anteiso-methyl-branched and cyclopropane fatty acids are noteworthy. Fatty alcohols (trace), sterols and sterol esters, and alkanes accounted for ~89% of the unsaponifiable matters, or 4.6% of the total lipid extract of the adult fly. It is worth noting that in the polar solvent extracted lipid (using chloroform:methanol), there was significant amount of non-lipid compounds in the oil that slowly precipitated after the storage of the lipid in the original solvent. More research is needed to fully identify these compounds.
3 Biorefining and Fractionation to Obtain Oil and Protein
Bioprocessing is necessary to produce protein concentrate or isolate and oil as feed or food ingredients, and for applications beyond food and feed. Fractionation may also reveal the fate of undesirable components present in the BSFL because of the contamination or composition of the BSFL diet. The general oil and protein extraction strategies are shown in Figure 4.
3.1 Oil extraction
Oil removal is the first step if further protein separation and concentration is desired. Several methods have been used to separate oil and protein from BSFL, including mechanical pressing, wet mode fractionation, aqueous extraction, solvent extraction, ultrasound-assisted, microwave-assisted, and enzyme-assisted solvent extraction. Larvae can be fractionated at the fresh or wet state (after a quick parboil to stabilize and prevent color change and natural degradation), or after drying that will allow the use of conventional extraction by non-polar solvents. Larvae browning caused either by enzymatic or non-enzymatic reaction should be prevented by stabilization [
22]. Fractionation of larvae at wet state is ideal for protein extraction because protein is not severely heat denatured, but the removal of lipids from wet biomass can be challenging.
Oil extraction from aqueous system requires blending and centrifugal separation of mixing induced formation of emulsion, and the lipid recovery yield is typically low, even with the assistance of proteases to destabilize emulsion, as seen in our earlier work [
23]. For lipid extraction from wet BSFL, larvae tissue breakage and emulsion formation are the major hurdles for oil extraction with high yield. It has been shown that aqueous extraction of BSFL oil is incomplete even at elevated temperature conditions, such as 95°C [
24], as shown in Table 4. Microwave-assisted and enzyme-assisted extraction have been developed in recent years with respective pros and cons; the former is superior in terms of short processing time and high oil yield, while the latter could extract oil but destroy the protein structure. In addition, the utilization of enzymes may not be economically feasible and efficient [
25]. Srisuksai et al. [
24] investigated the best oil extraction methods (aqueous at 45–95°C, mechanical pressing, ultrasound with hexane and ethanol) by comparing the fatty acid profiles, percentage yield, and antioxidant properties of BSFL oil. Ultrasonic extraction with hexane resulted in the highest yield, and aqueous extraction showed the highest lauric acid composition and free radical scavenging activities. In addition, high-temperature aqueous extraction resulted in higher oil yield and free radical scavenging activities than low-temperature extraction.
Oil extraction or defatting with organic solvents of more non-polar nature will require the drying of larvae biomass, and moisture content can significantly impact completeness of oil recovery. In large scale processes, hexanes is often used to extract oil as this technology has been fully developed. Despite solvent extraction being able to achieve a high yield of oil, this approach can be costly for infrastructure building, potentially hazardous, environmentally damaging, and it requires an extensive solvent recovery system. Defatting by organic solvent can recover the oil relatively completely, compared to an aqueous method with 19% to 60% oil extraction yield [
32].
An alternative solvent, 2-methyloxolane (2-MeO) cyclic ether, also known as 2-methyltetrahydrofuran, was tested in comparison to hexane in its lipid extraction performance and its effect on BSFL protein quality, as reported by Ravi et al [
29]. The 2-MeO solvent is derived from lignocellulosic biomass, thus is a biobased and biodegradable solvent. The oil yield, crude protein content, protein dispersibility index, solubility in alkaline solution, and urease index for the 2-MeO defatted flour were slightly better than the hexane defatted flour. Butane was also used to defat BSFL to produce protein meal to replace fishmeal for rainbow trout feeding. Subcritical butane removed lipid from BSFL almost completely at 35°C, 50 min/cycle, 5 times of extraction [
30]. Hexane:isopropanol (3:2) mixture was also used to extract oil from freeze-dried larvae [
33].
Mechanical pressing has been studied for oil removal. A temperature-controlled mechanical pressing of BSFL at 70–130°C led to a relatively high oil yield of 76%–79% oil recovery [
28]. However, the protein powder’s functional properties were different, with an alcohol-based method and protein extract having better water dispersion than that from mechanical pressing, but the latter contained more natural antioxidant compounds. Therefore, defatting method will impact nutritional, functional, and bioactive properties of larvae [
28,
34]. Mechanical extraction of oil by screw press was also modeled by Rudoy et al. [
35], and mathematical models were obtained to allow theoretically determination of the productivity using a screw pressing and its energy intensity in the processing of insect biomass.
It should be noted that larvae heating by blanching caused less separable oil by mechanical and enzyme assisted fractionation process [
36]. Blanching led to protein aggregation and entrapment of oil in the protein matrix, resulting in 25.0% loss in oil recovery, compared to only 3.3% loss for unblanched larvae. Blanching reduced cream layer and led to more pellets. Enzymatic treatment improved solubilization of pellet protein and resulted in an increased oil layer. This work showed that processing without blanching led to greater than 80% oil recovery from whole larvae. However, in both cases, only 50% of protein was recovered in the aqueous phase and the other 50% stayed in the pellet after centrifugation.
Oil extractability from BSFL as affected by killing and drying methods [
31] is also shown in Table 4. Cold acetone extracted relatively more oil from oven dried larvae compared to that dried by microwave oven and freeze-drying after blanching. It is worth noting that non-blanched and freeze-dried samples exhibited free fatty acid content of 55.8%–69.1% in the extracted oil, while the other oils showed much lower values (0.6%–2.6%). Such high degree of lipid degradation and prevention need to be further investigated.
3.2 Protein extraction
The most challenging aspect of BSFL biorefining is to separate protein in high yield and high purity. The inherent presence of chitin, a fibrous and insoluble polysaccharide, and the presence of highly insoluble protein are the key factors that can interfere with protein extraction, and these can also lower protein digestibility by monogastric animals. Insects contain significant amounts of “fiber” as measured by the crude fiber method which can include the sclerotized proteins, minerals and other compounds bound to the matrix. The BSFL cuticle is a network of proteins, lipids, minerals, and other compounds. Chitin is only present in the procuticle, the two innermost layers of the cuticle. The predominant compound in the cuticle of most insects is not chitin, but protein. The high concentration of valine, histidine, and glycine in the fiber fraction than in whole insect indicates their contribution to the relative strength, stiffness, elasticity and other physical properties of sclerotized and cuticular proteins [
18]. BSFL’s mineralized exoskeleton is rich in calcium and other minerals that are incorporated into the cuticle. Therefore, the presence of chitin and high concentration of minerals that crosslink or tightly bound to proteins to form highly insoluble scleroprotein [
18,
25,
37] make BSFL protein extraction very challenging. Table 5 summarizes some key evidence of protein extraction efficiency.
The methods used for extracting BSFL protein mainly comprise alkaline extraction, enzyme extraction, buffer solution extraction, and the use of Osborne fractionation protocol to study the type of protein according to solubility. Among these methods, the alkaline extraction method, as commonly used for oilseed protein extraction, is considered efficient, simple, and inexpensive, and it has high adaptability to industrial scale operation. However, many researchers have shown low protein extraction yield and the protein fractions having much lower protein content than those of plant protein extraction.
Mshayisa et al. [
33] showed after pH 10 extraction and pH 4.5 precipitation, the highest protein content of the extract was 73.4%, but the total amino acids was only 52.5%, and the extract still had 22.9% polysaccharide. Smets et al. [
38] conducted protein extraction from 3 life stages of larvae at pH 11 and precipitation at pH 4. The protein recovery ranged 27%–57%, and the extract had protein content of 85%–98%. The lowest recovery of 27.6% was from larvae, compared to that from prepupae and pupae. Tan et al. [
37] studied BSFL chitin extraction and found that the purified chitin fraction (even after protease hydrolysis) only had 9% chitin, and 68% was lipids, and 23% protein. Queiroz et al. [
39] showed protein extraction yield of 22.5% under 0.25 M NaOH at 40°C for 1 h, then pH 4.5 precipitation and this extract contained 61.1% protein. Ravi et al. [
40] on wet mode fractionation showed that the aqueous supernatant protein fraction which was about 43% of the total mass only had ~40% protein, and the centrifugation solid precipitate contained 52% protein. This was attributed to the strong association of proteins with other components (cross linked with chitin or sclerotized proteins). Caligiani et al. [
25] showed 71% protein recovery in supernatant (from fresh and non-blanched larvae at 1 M NaOH at 40 °C for 1 h) with 15% degree of hydrolysis-induced protein damage. The extraction residue had 17% of the total protein indicating an incomplete protein extraction. Pan et al. [
41] reported that high alkaline pH (10.5 to 12.5) improved extraction rate by up to 10 times relative to the control at pH 9, but no protein content information was given.
The protein extracted under extreme alkaline pH was partially unfolded, leading to a substantial reduction in the disulfide bonds, hydrogen bonds,
α-helix, and particle size; whereas notable increases in the absolute zeta potential, surface hydrophobicity, and protein dispersion were observed due to the increased repulsions between side chains [
41]. The solubility, foaming, and emulsifying properties of extracted proteins were significantly improved (especially at pH 12.5). A study suggested BSFL proteins are covalently bound to chitin [
44], and the typical protein extraction method was not effective in cleaving chitin-bound proteins. The protein content of the chitin-rich sample was shown to be 48.5%, and only 15.3% was chitin. The impact of chitin or other compounds tightly associated with protein on functional properties of protein extract is largely unknown.
Other means of improving protein extraction under alkaline pH have been investigated. Enzymatic hydrolysis can be applied during protein extraction or applied to extraction residue after the removal of soluble proteins. Enzymes can shorten the chains of protein and chitin, leading to a more soluble product. Enzymatic hydrolysis and alkaline solubilization used sequentially may potentially provide more refined separations, enabling the recovery of protein, peptides, and chitin in higher yield and purity. The reported protein recoveries using enzymatic hydrolysis range from 50%–80%. However, Chakawa and Goosen [
42] showed that enzymatic hydrolysis at pH 9–12 behaved like an alkaline extraction, as enzyme addition did not significantly increase protein recovery. A scaling-up trial on hydrolysis with alkaline protease and keratinase showed a reduction of the substrate by 81.1% compared to 47.7% of the substrate without proteases [
43]. The hydrolysate fraction had 61.9% crude protein, 54.1% total amino acids, and 88.3% of the peptides had molecular weights below 1000 Da. Through this process, 50.0 kg of defatted BSFL was transformed into 32.2 kg protein, 0.85 kg melanin, and 5.8 kg chitin. The screening of 7 proteases and optimization of enzymatic hydrolysis conditions led to the identification of the best enzymes which were alkaline proteases (
Bacillus subtilis source) and keratinase (
Bacillus licheniformis source) that can be used at 2%–3% of substrate quantity.
Xu et al. [
26] studied the effects of ultrasound-assisted alkaline extraction of larvae protein from boiled and oven dried then hexane defatted BSFL meal. Compared with those using the conventional hot alkali method, ultrasound-assisted extraction significantly increased protein extraction yield from 55.4% to 80.4% but slightly reduced the purity from 84.2% to 80.8%. The ultrasound assisted extraction increased the
in vitro protein digestibility from 83.0% to 99.8%. Moreover, ultrasound assisted extraction led to a more ordered secondary structure and more porous surface morphology of the protein, without breaking the peptide bonds. Ultrasound treatment also improved the solubility and emulsion capacity of the larvae protein.
Protein extraction can also be done by using salt and buffers. Bose et al. [
45] studied BSFL protein extraction and allergen mapping. LC-MS/MS-based proteomics experiments were used to assess the protein extraction efficiencies by a suite of extraction buffers and the effect of processing on proteome and allergen detection. SDS-based buffers yielded the maximum number of protein groups, and buffer composition and processing influenced allergen detection. Salting-in and salting-out coupled with ultrafiltration has been performed by Zozo et al. [
46], but no yield and purity data were provided. The influence of alkaline extraction (1 M NaOH at 60 °C for 30 min) and isoelectric precipitation method assisted by salting-in with 1% NaCl and salting-out with 80% (NH
4)
2SO
4 on the functional properties of BSFL proteins were studied [
46]. The addition of (NH
4)
2SO
4 significantly influenced the solubility of protein, particularly at pH 2, suggesting its potential applicability in acidic food systems. Salting-out methods reduced hydrophobicity and affected protein functionality. Salt (NaCl) was also used to optimize protein extraction [
47] in that salt concentration, extraction temperature, and blanching time on extraction yield and protein quality were examined using response surface methodology. The optimal blanching was determined to be at temperature of 85°C and for a duration of 12.4 s, and using a concentration of 0.46 M NaCl achieved maximal protein solubility. Significant improvements in protein functionality after blanching, particularly emulsification stability, were observed.
The author’s research group has also studied how BSFL drying (HD: commercial high-heat drying, FD: freeze-drying, and Fresh: freeze-thawed larvae) can affect types of proteins based on solubility as characterized by Osborne fractionation. The yield and protein content in different Osborne fractions are presented in Figure 5. It shows that drying can significantly impact protein extractability possibly due to the formation of different interactions between protein and other components in the larvae. It indicates that high-heat drying may strengthen the formation of “insect fiber” made of chitin-protein-mineral [
18], and this work supports the stated challenges of protein extraction and removal of interfering compounds from the protein extract. Much more research is needed in the space of biorefining of BSFL to maximize the yield and quality of protein extract, as well as to investigate the fate and mass balance of minor nutrients and/or harmful compounds during BSFL bioprocessing.
Although not a main focus point of this review, BSFL protein’s functional property is a very important application consideration. Defatting method, protein isolation process, and larvae drying can all significantly impact functional properties of BSFL. Marasca et al. [
31] showed ethanol extracted meal had higher water holding capacity, emulsion stability, water absorption index, and swelling capacity, but lower hygroscopicity compared to mechanically pressed meal. Whereas mechanical pressing led to more natural antioxidant compounds in the protein meal. Comparing BSFL defatted meal to that of mealworm (45% vs 65% protein content) [
48], BSFL had lower water binding, much higher fat binding ability, and much lower water solubility. At pH 4–5, the protein solubility of BSFL and mealworm were about 10 and 20%, and the corresponding solubility values at pH 10 were about 40 and 70%. BSFL’s protein concentrate’s functionality was also evaluated by Mshayisa et al [
33]. High protein content (73.4%) and water solubility (85%–97%, at pH 2 and above pH 8) were observed for the alkaline extracted and acid precipitated protein concentrate. Although processing is known to impact physicochemical and functional properties of the protein, such as reported by Haskaraca et al. [
31] that shows the impact of killing and drying methods, there is a knowledge gap in how different commercially viable drying technologies and degree of heating impact BSFL’s nutritional and functional properties, albeit a recent report by Wang et al. [
49] on 4 drying methods and compositional and structural profiles of the BSFL.
4 Using BSFL and Its Defatted Meals in Feed Formulation
From the available studies on including BSFL in feed rations for fish, poultry, and pigs, it has been shown only partial replacement of traditional feedstuff can be done due to the factors such as high fat and ash content, and varied degree of processing induced changes [
50]. Chitin in BSFL protein meal may present a problem for monogastric animals. Although chitin is recognized to have biological functions such as antibacterial activity and modulation of immune responses, most reports suggest that high levels of chitin can reduce the feed intake of livestock and poultry, and inhibit the intestinal absorption of nutrients, thereby decreasing protein digestibility. Consequently, chitin in BSFL protein is generally considered to be an anti-nutritional factor. Table 6 provides a summary of the discussion presented in the following sections.
4.1 For aquaculture
A review by Nica et al. [
51] on inclusion of BSFL, defatted or whole insects, in fish feeds for many fish species with 10%–100% protein replacement indicates that the inclusion did not negatively impact fish growth and feed conversion. Rainbow trout feeding using partially defatted BSFL meal to replace up to 50% of fishmeal had no negative effects on the weight gain and feed conversion ratio [
52]. The 30% and 45% replacement of fishmeal achieved significantly higher final body weight, weight gain and specific growth rate than the control group without causing a significant inflammatory response. It is suggested that BSFL can inhibit the apoptosis in intestine, which improves the intestine health of rainbow trout. However, the 75% replacement group had the lowest weight gain. Such high BSFL content in rainbow trout diets may have stimulated intestine inflammation. The major factors limiting inclusion of BSFL in aquafeed are reduction in protein digestibility, imbalanced amino acid profile, and increasing levels of saturated fatty acid [
59].
BSFL as an alternative protein source and its impact on crustaceans (shrimp and prawn) was reviewed by Ling et al. [
53] using papers published 2000 to 2023. A full spectrum of physiological and biological impacts, such as growth performance, feed efficiency, survival rates, body composition, and health was evaluated when replacing 10%–80% feed with BSFL. BSFL demonstrated a spectrum of effects from enhancing growth performance to influencing health and nutrient metabolism, varying with inclusion levels. Digestive enzyme activities, nutrient digestibility, antioxidant activities, immune responses, biochemical and metabolic parameters, and the health and morphology of intestinal and hepatic systems were discussed. Chitin has been associated with various health benefits for shrimp, including antioxidant properties, and potential immunomodulatory effects. However, high levels of chitin can pose challenges in growth performance and nutrient digestibility. It is suggested that longitudinal studies assessing the long-term impacts of BSFL feeding on various shrimp and prawn species are needed.
4.2 For broiler and layers
The nutritional benefits of BSFL meal for broiler chickens were reviewed using meta-analysis of 21 studies selected from 1878 published papers from 2016 to 2024 [
54]. Feeding BSFL at a ratio of 1:5 to 2:3 with basal diet had a favorable impact on weight gain, feed efficiency, carcass percentage, breast and thigh muscles, cooking loss, drip loss, and meat color. Favorable effects were also reported on physiological measurements such as erythrocytes, liver enzyme activities and other blood chemistry parameters. The impact of BSFL chitin is conflicting because it is indigestible by monogastric animals and may reduce the digestibility of proteins and feed efficiency. Because of this, the final weight of broiler chickens fell as the amount of BSFL in their diet increased. A review by Siddiqui et al. [
59] suggested that when used in poultry feed as an incomplete replacement for maize- or soy based feeds, BSFL produced similar performance as controls. Various studies have shown that 3%–15% BSFL meal inclusion in poultry diets enhanced their antioxidant status and can potentially boost immunity without compromising overall health.
Effects of BSFL meal on production performance, egg quality, and physiological properties in laying hens was reviewed by Fikri et al. [
55] using meta-analysis, since the reported findings have not been consistent. A total of 24 papers from 17 different countries were selected. The main findings are feeding laying hens BSFL meals had favorable effects on their feed efficiency, egg quality, and hens’ physiological responses. Xin et al. [
60] reported that mechanically produced BSFL protein meal, compared to hexane extracted meal, demonstrated better effects on the digestibility of nutrients in the feed for young laying hens due to the higher content of residual oil.
A few examples of BSFL’s digestibility in poultry are discussed as follows. The optimal substitution of BSFL for fishmeal in broiler chicken was determined and reported by Nampijja [
61]. The effects of partial to complete substitution (0–100%) on feed intake, feed utilization efficiency, growth performance, carcass characteristics, meat quality and economic benefits were assessed, and Table 7 highlights some observations reported. The optimal substitution based on feed conversion ratio was determined to be 54%.
The nutritional value of a partially defatted and a highly defatted BSFL meal were also determined for broiler chickens (26-day old, with 25% feed substitution) as reported by Schiavone et al. [
62] for apparent total tract digestibility coefficients (ATTDC) of nutrients, amino acid (AA) apparent ileal digestibility coefficients (AIDC), and apparent metabolizable energy. Significant higher digestibility was observed for partially defatted than for highly defatted BSFL meals. The AIDC of the AAs of partially defatted and highly defatted meals ranged from 0.44 to 0.92 and 0.45 to 0.99, respectively, but there was no significant difference, except for glutamic acid, proline and serine. The effects of pressed and solvent extracted BSFL meal at 25% feed substitution on metabolic energy and nutrient digestibility by laying hens of 63 day-old was investigated by Xin et al [
63]. Pressed meals showed significantly higher crude fat digestibility and total energy digestibility than solvent meal, and the digestibility of arginine and leucine in pressed meal was significantly higher than in solvent meal, while differences in lysine, cystine, threonine, tryptophan, and isoleucine were not significant. Drying method, conventional (60°C) vs microwave (500 W for 15 min) drying, can also impact nutritional properties of the BSFL protein as reported by Huang et al [
64]. Lysine and valine were the first limiting amino acids for such dried protein. The total sulfur-containing amino acids (methionine and cystine) of 3.4%–3.8% was higher than the FAO/WHO standard for older children, the aromatic amino acids were nearly three times as much, and histidine was about 2.5 times higher than the standard values.
The use of different insects, such as BSFL, mealworms, housefly, and crickets, as an alternative to soybean meal for poultry feeding has been reviewed by Belhadj Slimen et al [
65]. Results suggest equivalent or enhanced growth performances and quality of end-products as compared to fishmeal and soybean meal. In general, insect meals meet poultry requirements of essential amino acid composition, nutrient digestibility (with total tract digestibility of both essential and non-essential amino acids ranging from 0.83 to 1.00), and feed acceptance. However, the average apparent ileal digestibility coefficient of the AAs was greater in mealworm (0.86) compared to BSFL (0.68). The dry matter, crude protein, and oil digestibility are lower for BSFL compared to other insects as summarized in Table
8.
Heating or drying and further processing of the BSFL can destroy pathogenic agents, extend shelf-life, and facilitate incorporation of the insects in feeds, but these treatments can also impact nutritional quality. It was reported [
65] that heating treatments decreased the crude fat content in the order of toasting > boiling > oven-drying > solar-drying. This may be caused by heat-induced matrix interaction and binding. The observed increased content of crude protein and carbohydrates may be the results of the heat-stabilized biomass that prevented further biological degradation. However, extreme temperature and long heating time will cause degradation of polyunsaturated fatty acids and amino acids. There is a great need to conduct process optimization trials for maintaining nutrient integrity in feed-grade BSFL materials, and avoiding excessive Maillard reaction, matrix cross-linking and insolubilization, and oxidative degradation of protein, lipids, and other minor nutrients.
4.3 For swine and weaned pigs
Using BSFL as substitute for fishmeal with up to 100% replacement showed that the pig carcass weight at 50%–75% replacement was higher than for pigs fed control diet and with 100% replacement [
56]. Crude protein content of pork was not impacted by BSFL feeding. The beneficial effects of BSFL extract (containing 15% oil and other undisclosed components) on weaned pigs was shown to be reduction of diarrhea caused by porcine epidemic diarrhea virus [
66]. Intestinal histomorphological indicators and oxidative stress caused by the virus infection were improved, and such extract significantly promoted the mRNA expression level of antiviral-related genes in the ileum, thus explaining the improvement of intestinal function in piglets. Boontiam et al. [
57] also reported that feeding full-fat BSFL to weaning pigs improved growth performance, gut health, and antioxidant status compared to control. It also led to greater nutrient digestibility, immunoglobulin A and glutathione peroxidase levels, cecum weights, duodenal villus height, duodenal villus-to-crypt depth ratio, and cecal
Lactobacillus spp. Significantly decreased diarrhea rate and tumor necrosis factor-alpha were also observed. Therefore, by reducing gut inflammation and modulating antioxidant capacity, the BSFL improved piglet growth performance and nutrient utilization. Similar results are also observed by Phaengphairee et al [
67].
4.4 For ruminants
Chitosan from insect chitin shows promise in enhancing feed efficiency, rumen fermentation by promoting beneficial microorganisms and inhibiting pathogens, reducing methane emissions, and promoting animal health as reviewed by Piboonkunsamlit et al. [
58] and Kichamu et al [
6].
In vitro studies show that chitosan supplementing at 1.5 g/kg and 3.0 g/kg of dry matter intake can reduce methane emissions by up to 42%, mainly by affecting microbial hydrogen utilization. Additionally, chitosan supplementation can enhance immune function, reduce oxidative stress, and improve production parameters such as milk yield and quality, although results vary across species and experimental conditions. However, supplementing at higher level such as 10 g chitosan /kg feed may have negative impact on digestibility. There is a consensus that chitosan offers numerous benefits as a feed additive in ruminant production, and BSFL, a sustainable and abundant chitin source, offers a promising solution and replacement for the commercial chitosan derived from shrimp shells that can be prohibitively expensive. Kichamu et al. [
6] reviewed insect-based feed for ruminant farming. The results from many studies have demonstrated that insect nutrients, primarily amino acids, protein, and fat, are highly digestible, safe, and beneficial to ruminant health and productivity.
It was suggested that BSFL can drive transformative innovations in ruminant nutrition and pet food science (due to the immune enhancing properties). For ruminant production, the ingredients derived from BSFL are not only sustainable protein substitutes but also they can regulate the dynamics of the rumen microbiome, optimizing the volatile fatty acid profile to improve energy utilization efficiency [
7].
4.5 For pet
Kahraman et al. [
68] studied how substitution of poultry fat with BSFL oil in dog diets impact digestibility, palatability, and oxidation of dry food, as well as immunity, blood biochemistry, and fecal characteristics of adult dogs. With the full substitution of 6% fat, organic matter digestibility was lowered, and the total fatty acid concentrations in the feces decreased with the larvae oil substitution. Even though larvae oil reduced the protein digestibility and palatability of diets, there was no adverse effect on the health status of dogs, because serum biochemical parameters did not change significantly. However, it is suggested that the fatty acid profile that differentiates BSFL from other animal or plant oils must be considered for digestibility, intestinal fermentation products, health, and immune function [
68]. It was also reported that the inclusion of BSFL as either insect meals or oil in the diets of pet foods enhanced their antioxidative capacities, as indicated by the increase in the serum total antioxidant capacity, as discussed by Lai-Foenander et al [
69].
4.6 Allergen and toxicant consideration
Another important consideration of using BSFL in feed is potential allergens from this insect. Among the most pressing food safety concerns associated with edible insects is their potential to trigger allergic reactions. Allergenicity may arise from specific proteins found in insects, some of which resemble those present in shellfish, such as tropomyosin. Individuals or animals with shellfish allergies may therefore be at risk when consuming insect-based products [
70]. Allergic reactions to different insects and cross-reactivity with crustacean and inhalant allergens have been described, with the identification of new IgE-binding proteins besides the well-known allergens. Processing, such as heating, may affect (decrease or increase) the solubility, interaction with other matrix components, and the immunoreactivity of insect allergens, with results depending on species and type of proteins. Chemical and enzymatic hydrolysis, in some cases, can reduce immunoreactivity. However, the impact of treatment on the IgE-binding capacity does not necessarily correlate with clinical symptoms. Bose et al. [
45] found a total of 33 putative allergens by comparing the detected BSFL proteins to the sequences from public allergenic protein databases.
Other studies have focused on microbial and chemical safety of BSFL. Microbial and pathogen contaminants, heavy metals, mycotoxins, and pesticides are serious concerns. Although BSFL can efficiently degrade organic pollutants and can be used in biological detoxification of organic waste, it can bioaccumulate heavy metals, such as cadmium and lead, thus leading to high concentration of heavy metal in larvae biomass [
11]. BSFL has exhibited certain physiological tolerance to heavy metals such as cadmium and zinc (e.g., body weight is not significantly affected), but their potential bioaccumulation poses a concern. The safety of using whole larvae or defatted meal in feed formulation still needs to be carefully assessed [
7]. As discussed above, using biorefining for fractionation and studying the fates of these harmful compounds may help ameliorate these chemical safety concerns.
5 Using BSFL Production and Biorefining Side Streams as Biofertilizer
Black soldier fly frass, which is a mixture of insect excrements, leftover substrates, and exuviae (i.e., shed exoskeletons) has been studied and used as a sustainable organic fertilizer [
71]. Frass is typically produced 2 to 4 times the quantity of the larvae biomass harvested. Since the frass is obtained from various production systems and under different environmental conditions, its composition and biochemical properties, including nutrient contents, biostimulant compounds, and microbial profiles are largely varied. Proper compositions of BSF frass when used as fertilizer can increase the quality of plants and crops by establishing healthy soil and improving the plants’ immune systems. It can potentially replace the conventional chemical fertilizer to create a more sustainable cropping system by organic farming. It can also offer an alternative approach that can be integrated with conventional fertilizers to optimize the cropping system. Returning frass nutrients to soil and crops that can produce feed substrates for raising BSFL demonstrates a particular small cycle of resource use that contributes to the larger circular bioeconomy system.
A review conducted by Lomonaco et al. [
72] examined using frass as organic fertilizer and its composition and beneficial effects on different crops. The composition of micro- and macro-nutrients, pH, organic matter content, electrical conductivity, and moisture content of frass from different feeding substrates are presented, as well as the presence of potentially beneficial bacteria contained in the frass for plant growth. This work classified the crops studied into distinct groups, such as plant family of
Gramineae,
Asteraceae,
Cruciferous,
Lamiaceae,
Plantaginaceae, and
Solanaceae, which is useful to simplify comparisons in future research. Knowing the chemical composition of the frass makes it possible to understand which plant species it is best to apply frass with specific characteristics. The determination of the optimal dose of frass to trigger a positive response in certain plant parameters is very important, because beyond the optimal doses, a suppressive or deleterious effect can be observed.
Jiang et al. [
73] conducted a review on using BSFL frass to restore soil health. The frass is generally alkaline, with an average pH of 7.60 (ranged 4.97–9.52), organic matter content of 75.6% (ranged 17.1%–96.3%), and carbon to nitrogen (C/N) ratio of 17.4 (ranged 7.41–48.5). Organic matter breakdown can release essential nutrients such as nitrogen (N), phosphorus (P), and sulfur (S) for improving soil quality. This review and its meta-analysis indicate that frass has good physiochemical properties, like those of compost, and frass production requires a shorter time than aerobic composting. Bioactive compounds, such as antimicrobial peptides (AMP) (BSFL genome encodes about 50 AMPs) are found in frass. Chitin has been demonstrated to promote plant growth, and it also has been shown to remediate polluted soils by absorbing heavy metals and antibiotics. The derivatives of chitin by soil microorganisms, such as chitosan and glucosamine, can lead to improved plant adaptability to abiotic stresses and soil-borne diseases. Therefore, BSFL chitin can improve soil structure, fertility, and plant immunity [
1]. The presence of humic substance is another advantage of BSFL frass over mineral fertilizers. Increasing evidence also indicates that BSFL frass may harbor plant growth-promoting microorganisms or that the bioconversion process is conducive to their reproduction. Because of frass’s positive impact on soil microbial metabolic activity, it can reverse soil microbial dysbiosis and suppress soil-borne plant diseases as reviewed by Jiang et al [
73].
The beneficial microbes in the frass can promote soil and plant health. However, to meet the microbiological requirements for the use of insect frass as a biofertilizer or soil improver, a heat treatment of 70 °C for 60 min is often needed to destroy pathogens. Thus, there is a need to identify and understand the most effective heating method for preserving the beneficial microorganism present in the frass and, at the same time, ensuring that no pathogens or live larvae are released into the environment.
BSFL protein in the frass or when using the protein extraction residue that still has substantial amount of insoluble proteins and that is rich in chitin, are also expected to improve soil health by enhancing population and activities of beneficial soil microorganisms, such as ammonifying, nitrifying and nitrogen-fixing bacteria and inorganic phosphate-solubilizing bacteria, thus increasing the available nutrients in the soil [
74–
76]. Using peptides and amino acids as plants’ biostimulants can mitigate plant injuries caused by abiotic stresses, and regulate nitrogen uptake and root development [
74]. The chitin and chitosan rich biorefining co-products, such as extracts from BSFL pupal exuviae, activated auxin signaling in a transgenic tomato model and exhibited fungicidal activity against
Fusarium [
77]. Thus, such products are expected to act as plant biostimulants. Alternative biofertilizer based on biorefining waste streams and with additional functional properties, in addition to providing nitrogen, phosphorus and potassium, holds exciting potentials.
6 Using BSFL Oil in Biofuel Production
BSFL oil’s use as biodiesel feedstock has been reported and this oil’s general suitability in biofuel production and future directions have been recently reviewed by Odoi-Yorke et al [
78]. A review by He et al. [
79] on BSFL biodiesel production and cost reduction indicates the presence of a number of non-triacylglycerol components, including colloidal substances and oxidizing intermediates, that should be removed by purification. Impurities can lead to thermal instability and fuel oxidation that can limit its applications.
A novel application of BSFL is the use of its oil for sustainable aviation fuel (SAF) production via the hydroprocessed esters and fatty acids synthetic (HEFA) pathway. The U.S. government aims to boost domestic SAF production to 3 billion gallons per year by 2030 and 35 billion gallons by 2050 through its landmark “SAF Grand Challenge” initiative launched in 2021. However, the production capacity was estimated at 15.8 million gallons in 2023 [
80], far below the SAF Grand Challenge’s nearest target and the 17 billion gallons of jet fuel consumed in 2019. Figure 6 shows the U.S. SAF production capacity in comparison to other biofuel production from 2021 to 2025 (EIA of U.S. Energy Information Administration). Other biofuels presented in the figure include SAF, renewable heating oil, renewable naphtha, renewable propane, renewable gasoline, and other emerging biofuels that are in various stages of development and commercialization. SAF production capacity is only an estimate based on company announcements and only includes HEFA SAF. With SAF production capacity now about 460 million gallons and growing in 2025, SAF production is expected to drive most of the total biofuel growth. Despite the strong growth trend in SAF, the absolute volume remains relatively low, making up less than 2% of about 26 billion gallons of U.S. jet fuel consumption in 2025. The Sustainable Aviation Fuel Market Outlook 2025 (5
th edition) released by SkyNRG & ICF also predicts the SAF production capacity reaching 6 billion gallons in 2030, and SAF demand to be 13.2 billion gallons by 2035, primarily driven by government mandates, such as those from EU and UK that started in January 2025, and approximately 60 airlines having set specific SAF targets for 2030.
The biggest barrier for SAF production remains its price and profitability, which is currently 2–10 times more expensive than fossil jet fuel. SAF has thus far been predominantly produced through HEFA from oil extracted from oilseeds and from waste, such as used cooking oil and tall oil, for which the HEFA process has been primarily optimized. However, oilseed feeds for HEFA SAF production have high environmental loas and price. Any less expensive starting feed, such as waste oil, is more desirable. In this regard, BSFL oil offers an exciting and potentially cheaper alternative to oilseeds. First, BSFL oil does not have the same land-use constraints compared to oilseeds as insects are reared on a smaller area in an intensified industrial process. Second, BSFL oil is unique due to its relative richness in lauric acid (C12:0) that is relatively irrespective of the larvae production conditions, offering a unique homogenous oil feed for HEFA SAF production, which is an advantage in process engineering. Its lauric acid and high degree of saturation suggest that its HEFA processing could be performed more efficiently with less hydrogen input. The BSFL oil will allow for a unique opportunity to explore BSFL-specific HEFA process optimization to produce three of the four chemical constituents that make up conventional jet-A fuel (aromatics, cycloalkanes, iso-alkanes, and n-alkanes) as shown in Figure 7, leading to the realization of a 100% HEFA SAF replacement for Jet-A fuel. The BSFL oil derived SAF may also have a very desirable carbon chain length profile, i.e. shorter than that from seed oils. Currently, oilseed-derived HEFA SAF is predominantly composed of n-alkanes, which has a lower energy density, and can only be used in 50% blends with Jet-A [
81]. There has been no comprehensive evaluation of HEFA SAF from BSFL oil.
The HEFA process is relatively mature, and it is one of the oldest approved SAF production pathways. However, innovations in the catalytic conversion of fats and oils to HEFA SAF via hydrodeoxygenation and hydroisomerization to produce cycloalkanes and isoalkanes in higher concentrations than commonly seen in HEFA SAF are needed. Creation of new catalysts for one-pot reaction and for having higher tolerance for oil impurities and poisoning are also needed. BSFL oil, depending on how it is extracted and solvent used, can contain different amounts of organic or inorganic forms of mineral compounds which may negatively impact catalytic performance or affect the quality of the HEFA SAF. Therefore, developing specific oil purification methods that are effective in removing contaminants from oils with wide range of impurity will be a crucial need for SAF production from BSFL oil. This is a significant gap in knowledge and publication.
At the current commercial scale and capability of BSFL production, the larvae oil is more expensive than commodity vegetable oil for biofuel production. However, if insects are raised on feed contaminated with mycotoxin, pesticides, veterinary drugs, hormones, dioxins, or heavy metals, additional biorefining treatments are not only necessary to obtain the valuable insect protein, such fractionated and likely contaminated oil will also provide a more suitable and cost competitive feedstock for biofuel production.
7 Specialty Products and Bioactivities Derived from BSFL
BSFL also finds its applications in the field of nutraceutical and cosmeceuticals [
69] due to its antimicrobial, antioxidant, anti‐inflammatory, and wound healing effects. BSFL and its fractionated products have shown to have antibacterial activity against
Escherichia coli and
Streptococcus suis, and prebiotic potential [
44]. The prebiotic activity of the whole larvae, its protein isolate, and chitin-rich pellet was shown for
Limosilactobacillus reuteri, a naturally occurring species in the gastrointestinal tract of pig.
Besides the lauric acid, the antimicrobial ability can be from larvae’s high level of adaptability for growing conditions and broad‐spectrum resistance against pathogens. BSFL possesses the largest antimicrobial peptides (AMP) gene family among all insects. AMPs are gaining attention as potential alternatives due to their low production costs, antimicrobial activity against a wide variety of microorganisms by the membranolytic mechanism or by interacting with functional proteins and genetic materials, high heat tolerance, and low toxicity to eukaryotic cells. Since BSFL can also accumulate antimicrobial compounds from their diet and modulate according to its pathogen load, research on effect of substrate properties on antimicrobial capacity of the BSFL is an exciting topic to explore. There is a possible association between the diets of BSFL and their subsequent bioactive composition. Table 9 summarizes key bioactivities of BSFL components discovered so far and as reported in the literature.
7.1 BSFL oil
The BSFL oil has been reported to have strong antibacterial properties due to the high lauric acid content. Shu et al. [
83] reported its antimicrobial activity against
E. coli in vitro. The exact mechanisms have not been fully elucidated; however, its amphipathic nature caused destabilization of bacterial cell membranes.
In vitro studies have shown that lauric acid has a broad-spectrum antibacterial activity against many bacterial pathogens, such as
Staphylococcus aureus,
Mycobacterium tuberculosis,
Listeria monocytogenes,
Clostridium perfringens,
Enterococcus faecalis, and others. Dietary lauric acid supplementation also enhanced the gut microbiota and intestinal health of black sea bream [
84]. Pathogenic bacteria such as
Lactococcus and
Vagococcus species were reduced by feeding BSFL to rainbow trout [
85].
BSFL oil has shown anti-inflammatory properties
in vivo in a metabolomic study against ulcerative colitis [
86]. Such anti-inflammatory activity was compared to free lauric acid using TLR4- or TLR2-activated THP-1 and J774A.1 cell lines to assess its putative protective effect against dextran sulfate sodium-induced acute colitis in mice. Both treatments suppressed proinflammatory cytokines release in LPS-stimulated macrophages; however, only BSFL oil exerted anti-inflammatory activity in Pam3CSK4-stimulated macrophages. Additionally, anti-inflammatory eicosanoids, i.e. oxylipins, and isoprenoids were identified in the BSFL oil that may contribute to the orchestrated anti-inflammatory response.
In vivo, a BSFL oil-enriched diet (20%) ameliorated the clinical signs of colitis, as indicated by improved body weight recovery, reduced colon shortening, reduced splenomegaly, and an early phase of secretory IgA response. These results indicate a novel beneficial use of BSFL oil as a modulator of inflammation.
BSFL oil has also been shown to modulate immunometabolic processes [
87]. A saponified form of the oil that contains lauric acid and other lipid-soluble metabolites may have interacted with metabolic signaling pathways. Using a primary human peripheral blood mononuclear cell, this study demonstrated that the saponified lipid solubilized in bovine serum albumin solution phenotypically suppressed the secretion of pro-inflammatory cytokines without altering anti-inflammatory cytokine levels. This work provided novel experimental evidence supporting BSFL oil’s role in immunometabolism as a dual regulator by suppressing NF-κB-mediated inflammation while promoting PPARδ activity.
7.2 Protein and peptides
BSFL has been reported to possess scavenging abilities against reactive oxygen species (ROS). The larvae protein and its hydrolysate may have been mainly responsible for this activity. Praseatsook et al. [
88] studied the antioxidant effect of BSFL protein hydrolysates using alkali extracted proteins that were hydrolyzed by Alcalase and bromelain. Alcalase hydrolysate showed optimal antioxidant activity at 3% (w/w). The hydrolysate was further fractionated into molecular weight (MW) groups ( > 30, 10–30, and < 3 kDa) and the highest antioxidant activity was observed in the MW > 30 kDa fraction. The effect of size of peptides on antioxidant activity was also reported by Angeletti et al. [
89] and many others.
Praseatsook et al. [
90] have also shown that BSFL protein hydrolysates and peptides had chemopreventative effects in a rat model of early-stage colorectal carcinogenesis by oral administration. The treatment significantly reduced aberrant crypt foci without affecting apoptosis, restored microbial species richness, and shifted gut microbial diversity disrupted by carcinogen exposure. Short chain fatty acid-producing and signature anti-inflammatory bacteria were enhanced. Such results support
in vivo chemopreventative potential of using BSFL protein hydrolysate as a functional food ingredient for promoting gut health and reducing colorectal cancer risk.
BSFL peptides have also been shown to possess anticancer effect. The antioxidant, anti-inflammatory (nitric oxide production in RAW 264.7 cells), antimutagenic (Ames test), and anticancer activities of BSFL-derived bioactive peptides and their molecular mechanisms were investigated by Praseatsook et al [
88]. Even though the MW > 30 kDa protein hydrolysate fraction exhibited the highest antioxidant capacity, the fraction having MW < 3 kDa exhibited significant antimutagenic effects, reduced nitric oxide production, and decreased cancer cell viability. Therefore, BSFL protein-derived bioactive peptides may have potential as multifunctional agents for cancer chemoprevention.
7.3 For cosmetics industry
It was reported that the major lauric acid of BSFL oil is favorable for the preparation of rinse-off cleaning products such as soap, shower gel, detergent, and shampoo [
91]. As lauric acid might disrupt the lipid structure of the skin, it is less appropriate for use in leave-on cosmetics and skincare products such as cream and lotion. Nevertheless, skincare products containing BSFL oil have been patented and claimed to enhance skin conditions through moisturizing, smoothing, tightening, and revitalizing actions [
92]. Based on the bioactivities BSFL has, the prospects of using it as a natural ingredient in cosmeceutical products are promising, particularly when the demand for “greener” cosmetics is ever increasing. There is much knowledge gap to be filled to understand the relationship between the BSFL extract or components and skin function improvement.
7.4 Identification of an anti-freezing component in BSFL albumin extract
A unique property of BSFL’s albumin fraction has been recently reported as having a strong ice recrystallization inhibition (IRI) activity [
93] as shown in Figure 8. The column fractionated protein components in the albumin fraction obtained by water extraction from the defatted BSFL meal showed a 40.4%–79.9% reduction in ice crystal size compared to a control at 1% concentration and under a wide pH (3–9) and salt (10–200 mM NaCl) concentration. A cuticle protein tentatively identified in the mixture has demonstrated strong H-bonding and structural flexibility by molecular dynamic simulations as outlined in Figure 8. This is the first time BSFL protein is reported to possess strong IRI activity, and such protein extract can be feasibly obtained compared to other naturally occurring antifreezing proteins.
8 Need for Comprehensive Technoeconomic and Life Cycle Analyses for BSFL Production and Utilization
There are numerous studies on environmental life cycle and gas emission assessments of BSFL raised on different types of substrates. However, there is a knowledge gap in technoeconomic analysis of the BSFL production, biorefinery, and application value chain. Kumar et al. [
94] analyzed the agronomic, environmental, and techno-economic benefits of BSFL farming. They highlighted the potential of BSFL as a cost-effective and ecologically sustainable bioconversion platform, that integrates organic waste valorization with the production of renewable animal feed, bioenergy, and value-added bioproducts.
Environmental sustainability assessment of utilizing BSFL for organic municipal solid waste valorization for biodiesel and animal feed production was reported by Hosseingholilou et al [
95]. The biorefinery included larvae drying (microwave and a combined infrared-hot air device), oil extraction (mechanical and solvent-based methods), and biodiesel production (conventional and ultrasound-assisted transesterification). The consequential life cycle assessment was conducted to examine the environmental performance of waste-to-biofuel scenarios. The scenario with an infrared-hot air drier, solvent-based oil extraction, and ultrasound-assisted biodiesel production yielded optimal environmental outcomes. Compared to other biodiesel feedstocks, such as waste cooking oil, rapeseed oil and soybean oil, BSFL oil demonstrated superior performance across environmental impact categories. A review on global research trends from 2010 to 2023 and future directions for sustainable biofuel production was conducted by Odoi-Yorke et al [
78]. It highlighted BSFL’s efficiency in converting various organic wastes into high-quality biodiesel and biogas, contributing to the global efforts in renewable energy and circular economy practices. He et al. [
79] also reviewed cost reduction approaches for BSFL derived biodiesel.
Life cycle assessment and environmental impact analysis for producing dried BSFL from biowaste conversion was reported by Nugroho et al [
96]. Five environmental impact categories (global warming potential, acidification, terrestrial eutrophication, fossil fuel depletion, eco-toxicity) were assessed. Producing prepupa was found to have the highest hotspots, followed by larvae drying. It was suggested that implementing integrated rearing system and using alternative drying methods may reduce environmental impacts. A challenge in evaluating greenhouse gas and ammonia emissions of BSFL production is the large variation in assessment methods, such as gas sensing techniques, as well as unclear factors influencing emissions, especially for nitrous oxide [
96]. Therefore, a set of guidelines should be developed to standardize technical approaches for establishing system boundaries, functional units, allocation, and system expansion assumptions.
Large-scale commercialization of BSFL production and utilization requires further research to optimize rearing parameters, refine extraction methodologies, and establish regulatory standards to ensure product safety and economic viability. Unique feed values and benefits for animal production in all approved species through fundamental research are needed to ensure long-term success. More work, such as the strength-weakness-opportunity-threat analysis on insect-based feeding for ruminant recently reported by Kichamu et al [
6], is also needed. Consistent and strong government policy and support are essential for successful technology adoption. The benefit and economic analysis also should include the potential to produce and commercialize other low volume but high-priced bioactive ingredients.
9 BSFL Industry Today
The nascent BSFL industry is likely to be on the forefront of developing the most promising technologies for recovering resources from diverse organic and animal wastes to produce proteins and oils that may have nutritional and functional benefits beyond traditional applications. The leading players for waste utilization and feed production who have large-scale facilities globally are InnovaFeed in France who has built the world's largest insect farm in partnership with ADM in Decatur, Illinois, USA, AgriProtein in South Africa, and Protix in Netherlands who has recently secured a major investment from Tyson Foods. The major players in North American are Enterra Feed Corporation in Canada, and EnviroFlight in USA who was acquired by Darling Ingredients, a global rendering and biofuel giant. There are a few other significant producers such as Nutrition Technologies in Malaysia with the ideal tropical climate and organic side-streams from palm oil production, Protenga in Singapore, and Hexafly in Ireland with a strong R&D focus.
While a few pioneering and vertically integrated companies are likely profitable or on the cusp of profitability, most of the industry is not yet consistently profitable on a standalone basis. Most companies are still in a capital-intensive scale-up phase, relying on investor funding and grants to build infrastructure and market share. The ability to maximize the use of all products, such as frass as biofertilizer, oil in feed, pet food, cosmetics or biofuels, and high-quality protein in food or feed formulation, is the key for future success. Creating unique applications with potentially high profit margin depends on the R&D activities within the companies and in collaboration with academic institutions. Low-cost feedstocks, automation, energy use management on the scaled-up processes to reduce production or operational costs are critical factors to address. The industry leaders who have built advanced automated factories and secured long-term agreements with major players in the feed, pet food, and fertilizer industries are in a good position to succeed. As the demand for sustainable protein, waste reduction, and replacement for the high-cost fishmeal remains high, the research and commercial development in BSFL production and bioprocessing are expected to continue.
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