Recombinant expression and characterization of the endochitinase Chit36-TA from Trichoderma asperellum in Komagataella phaffii for chitin degradation of black soldier fly exuviae.

The natural polymer chitin is an abundant source for valuable N-acetylchitooligosaccharides and N-acetylglucosamine applicable in several industries. The endochitinase Chit36-TA from Trichoderma asperellum was recombinantly expressed in Komagataella phaffii for the enzymatic degradation of chitin from unused insect exuviae into N-acetylchitooligosaccharides. Chit36-TA was purified by Ni-NTA affinity chromatography and subsequently biochemically characterized. After deglycosylation, the endochitinase had a molecular weight of 36 kDa. The optimum pH for Chit36-TA was 4.5. The temperature maximum of Chit36-TA was determined to be 50 °C, while it maintained > 93% activity up to 60 °C. The chitinase was thermostable up to 45 °C and exhibited ~ 50% activity after a 15 min incubation at 57 °C. Chit36-TA had a maximum specific enzyme activity of 50 nkat/mg with a Km value of 289 µM with 4-methylumbelliferyl-N,N',N″-triacetyl-ß-chitotrioside as substrate. Most tested cations, organic solvents and reagents were well-tolerated by the endochitinase, except for SDS (1 mM), Cu2+ (10 mM) and Mn2+ (10 mM), which had stronger inhibitory effects with residual activities of 3, 41 and 28%, respectively. With a degree of hydrolysis of 32% applying colloidal shrimp chitin (1% (w/v)) and 12% on insect larvae (1% (w/v)) after 24 h, the endochitinase was found to be suitable for the conversion of colloidal chitin as well as chitin from black soldier fly larvae into water-soluble N-acetylchitooligosaccharides. To prove scalability, a bioreactor process was developed in which a 55-fold higher enzyme activity of 49 µkat/l and a tenfold higher protein expression of 1258 mg/l were achieved.

Unlocking the potential of black soldier fly frass as a sustainable organic fertilizer: A review of recent studies.

Using Hermetia illucens, or Black Soldier Fly (BSF) frass as an organic fertilizer is becoming increasingly popular in many countries. As a byproduct derived from BSF larvae that feed on organic waste, BSF frass has tremendous potential for preserving the environment and promoting the circular economy. Since it has diverse biochemical properties influenced by various production and environmental factors, further research is needed to evaluate its potential for extensive use in crop production and agriculture. Our review summarizes recent findings in BSF frass research by describing its composition and biochemical properties derived from various studies, including nutrient contents, biostimulant compounds, and microbial profiles. We also discuss BSF frass fertilizers' effectiveness on plant growth and contribution to environmental sustainability. Great compositions of BSF frass increase the quality of plants/crops by establishing healthy soil and improving the plants' immune systems. Special emphasis is given to potentially replacing conventional fertilizer to create a more sustainable cropping system via organic farming. Besides, we discuss the capability of BSF bioconversion to reduce greenhouse gas emissions and improve the socioeconomic aspect. The prospects of BSF frass in promoting a healthy environment by reducing greenhouse gas emissions and improving the socioeconomic aspects of communities have also been highlighted. Overall, BSF frass offers an alternative approach that can be integrated with conventional fertilizers to optimize the cropping system. Further studies are needed to fully explore its potential in establishing sustainable system that can enhance socioeconomic benefits in the future.

Selective cytotoxicity of standardised n-hexane extract of black soldier flies' larvae on cancerous skin cells mitochondria isolated from rat model of melanoma.

INTRODUCTION: Melanoma is known as a highly lethal cancer. In melanoma cells, apoptosis signalling which relies heavily on the acute activity of mitochondria and reactive oxygen species (ROS) formation is suppressed. Our previous studies on natural compounds on melanoma suggested that mitochondria are a potential target for the melanoma treatment by selective cytotoxic effect of them. The black soldier fly is an important environmental protectant insect that based on recent studies induces apoptosis in liver and colorectal carcinoma cells through the activation of caspase 3, 8, and 9 and ultimately inhibits the growth of cancer cells. PURPOSE: This study was designed to evaluate the selective apoptotic effect of the n-hexane BSFL extract (BSFLE) on skin mitochondria. MATERIALS AND METHODS: The mitochondria isolated from melanoma cells were treated with various concentrations (1500, 3000, and 6000 µg/ml) of n-hexane BSFLE Then MTT viability assay, ROS determination, Mitochondrial Membrane Potential (MMP), mitochondrial swelling, cytochrome c release determination, and % apoptosis were performed. RESULTS: MTT assay showed that different concentrations of n-hexane BSFLE significantly (P < 0.05) decreased the SDH activity in cancerous skin mitochondria with the IC50. The ROS production and mitochondrial swelling results also showed that all concentrations of BSFL extracts significantly increased. MMP decline and the release of cytochrome c in cancer groups mitochondria. BSFLE increased apoptosis on melanoma cells. DISCUSSION AND CONCLUSION: It is suggested that n-hexane BSFLE compounds selectively induce a cascade of proapoptotic events that are probably defective in cancer cells. Most of these compounds target the mitochondrial transient pore caused by disruption of the mitochondrial respiratory chain. These events lead to disruption of the temporary permeability of mitochondria, swelling of mitochondria and finally the formation of apoptosome in the cytosol.

Nano-emulsified black soldier fly oil concerning performance traits, health, and immunity of broilers.

In the antibiotic-free era, traditional antibiotics have been suggested as alternatives to antibiotic-based growth promoters. Among the various methods, self-nano-emulsifying drug delivery systems (SNEDDS) are increasingly utilized to improve the bioavailability of oils containing essential substances. In this study, we evaluated the effects of black soldier fly oil (BSFO) SNEDDS in chicken drinking water on growth performance, small intestine histomorphology, and poultry health status. We divided 225 male Indian River strain broiler chickens into five treatment groups, each consisting of 5 replicates. The chickens were reared from to 0 to 35 d of age in a controlled environmental housing system. The BSFO SNEDDS was administered via drinking water. Treatments included ordinary drinking water (P1), bacitracin (P2), and 10 mL/L (P3), 20 mL/L (P4), and 30 mL/L (P5) BSFO SNEDDS. The observed parameters included growth performance, carcass yield, blood hematology, intestinal histomorphology, digestive microflora, and immunoglobulin (Ig) levels. Data were analyzed using analysis of variance (ANOVA) and Duncan's test. The results indicated that administering BSFO SNEDDS via drinking water improved feed conversion (P < 0.05), enhanced the performance index (P < 0.05), increased carcass percentage (P < 0.001), and increased the weight of the carcass parts. Additionally, it increased villus height (P < 0.01), lowered jejunal pH (P < 0.001), reduced pathogenic bacteria in the jejunum, and decreased the leukocyte count. BSFO SNEDDS in drinking water is expected to be used as a traditional antibiotic with the potential to replace synthetic antibiotic growth promoters in broiler chickens.

Increasing levels of fishmeal replacement by defatted black soldier fly larvae meal reduced growth performance without affecting fillet quality in largemouth bass (Micropterus salmoides).

A 90-day feeding trial was conducted to evaluate the effects of replacing dietary fishmeal (FM) with defatted black soldier fly larvae meal (BSFL) on the growth performance and fillet quality of largemouth bass (Micropterus salmoides). The largemouth bass was divided into six groups (BSFL0, BSFL15, BSFL30, BSFL45, BSFL75, and BSFL100) and fed six isonitrogenous(CP 50%, 508 g/kg) and isolipid (CL 9%, 124 g/kg) diets, in which 0, 15%, 30%, 45%, 75%, and 100% of the fishmeal was replaced with BSFL, respectively. The results showed that the final body weight (FBW) and specific growth rate (SGR) of the largemouth bass decreased with increasing BSFL content, and they were significantly lower in BSFL75 than in BSFL0. The weight gain rate (WGR) decreased with increasing BSFL content and the feed conversion ratio (FCR) of largemouth bass increased with increasing BSFL content. The saturated fatty acids (SFAs) and n-3 polyunsaturated fatty acids (PUFA) contents of the largemouth bass fillet significantly decreased, and the n-6 PUFA content of the largemouth bass fillets significantly increased with increasing dietary BSFL. The fillet b* significantly decreased with increasing BSFL content. The biological parameters, fillet proximate nutrient composition, fillet amino acid composition, skin color, and fillet texture of the largemouth bass were not affected by the replacement of BSFL. Transcriptomic analysis revealed that BSFL replacement of FM affects the immune system and metabolic processes of largemouth bass through signaling pathways such as complement and coagulation cascades, the PPAR signaling pathway, cholesterol metabolism, and fat digestion and absorption. In conclusion, a replacement level lower than 45% BSFL was suggested for the overall growth and fillet quality of largemouth bass.

The Allergen Profile of Two Edible Insect Species-Acheta domesticus and Hermetia illucens.

SCOPE: Edible insect proteins are increasingly introduced as an alternative sustainable food source to address the world's need to feed the growing population. Tropomyosin is the main insect allergen; however, additional potential allergens are not well characterized and the impact of extraction procedures on immunological reactivity is unknown. METHODS AND RESULTS: Proteins from different commercial food products derived from cricket (Acheta domesticus) and black soldier fly (BSF) (Hermetia illucens) are extracted using five different extraction buffers. The proteins are analyzed by SDS-PAGE and immunoblotting using allergen-specific antibodies and crustacean allergic patient sera. IgE binding bands are analyzed by mass spectrometry as well as the complete allergen profile of all 30 extracts. Urea-based buffers are most efficient in extracting insect allergens. Shrimp-specific antibody cross-reactivity to tropomyosin from cricket and BSF indicates high sequence and structural similarity between shrimp and insects. Additional unique allergens are identified in both species, including hemocyanin, vitellogenin, HSP20, apolipophorin-III, and chitin-binding protein. CONCLUSIONS: Identifying potential allergenic proteins and their isoforms in cricket and BSF requires specific extraction approaches using urea-based methods. While tropomyosin is the most abundant and immunoreactive allergen, seven unique allergens are identified, highlighting the need for insect species-specific allergen detection in food products.

Moving towards fully circular insect production: A focus on insect-derived biowastes.

Over the last decade, commercialization of insects for food and feed has been exponentially increasing. Insect protein is emerging as a sustainable livestock feed and human food alternative due to its low land and carbon footprint. The principles of insect industry are deeply embedded in the core values of sustainability and circular economy. Black soldier fly (BSF) is the crown jewel of insect industry and is one of the most commercially farmed insects. However, this steadfast growth is accompanied by generation of insect based biowaste such as dead flies and pupae exuviae. This will be a major waste fraction from this industry. This study discusses the valorization potential of this waste into chitin (which finds application in cosmetics, bioplastics, and pesticides, among other industries), biogas, fertilizer, and biochar. There is need to conduct more explorative research on value proposition of insect based biowaste to ensure that this industry can comply fully with circular economy and sustainability principles.

Recirculating frass from food waste bioconversion using black soldier fly larvae: Impacts on process efficiency and product quality.

Biowaste generation is increasing worldwide and inadequate disposal has strong negative impacts on food systems and ecosystems. Biodigestion of biowaste using black soldier fly (Hermetia illucens) larvae (BSFL) generates valuable by-products such as animal feed (larval biomass) and organic fertiliser (frass). However, the latter is typically unstable immediately after waste conversion and is thus unsafe for use as a fertilizer in terms of maturity. This study evaluated recirculation of frass within bioconversion of post-consumer food waste (FW) as a dietary component for BSFL to improve the quality of the subsequent frass obtained. Frass was introduced at increasing inclusion levels replacing food waste (2.5-100% on wet-weight basis) as part of the larvae's feeding substrate. Bioconversion efficiency and material reduction were significantly reduced by frass inclusion, while larval yield per experimental unit remained unchanged. When considering only the waste component in the larval diet, larval yield (dry-weight basis) ranged between 207 (0% frass inclusion) and 403 (40% frass inclusion) kg tonne FW-1, thus increasing by up to 94% at higher frass inclusion. With increasing dietary inclusion rate of frass from 0% to 100%, crude protein content of larval biomass increased by 41%, while fat content was reduced by 32%. The recirculated frass (obtained after including frass in the larval diet) had elevated concentrations of P, K, S, Na and B and around 6% lower organic matter content, demonstrating a higher degree of decomposition. Frass inclusion in the larval diet generated recirculated frass that were more stable and mature, as indicated by self-heating capacity, CO2 and NH3 volatilisation, seed germination bioassays and other parameters. It was concluded that frass recirculation improves waste bioconversion efficiency in relation to food waste unit, as well as larval biomass and frass quality, ensuring safer use as a fertilizer.

High expression of serine protease, Brachyurin in the posterior midgut of black soldier fly (Hermetia illucens) during horse dropping processing.

OBJECTIVE: Livestock droppings cause some environmental problems, but they have the potential to be used as effective biomass resources. The black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), is suitable for efficiently processing such resources. By using BSF larvae for the disposal of livestock droppings, we can obtain two valuable products: protein resources and organic fertilizer. However, there is insufficient research on the digestive enzymes suitable for processing this waste. Here, we aimed to construct an efficient BSF processing system using livestock droppings, and we explored the digestive enzymes involved in this process. RESULTS: First, we investigated the characteristics of transcripts expressed in the midgut of BSF larvae and found that immune response-related genes were expressed in the midgut. Then, we investigated digestive enzymes and identified a novel serine protease, HiBrachyurin, whose mRNA was highly expressed in the posterior midgut when BSF larvae fed on horse droppings. Despite the low protein content of horse droppings, larvae that fed on horse droppings accumulated more protein than those in the other groups. Therefore, HiBrachyurin may contribute to digestibility in the early stage of protein degradation in BSF larvae fed on horse droppings.

Synergistic impacts of antibiotics and heavy metals on Hermetia illucens: Unveiling dynamics in larval gut bacterial communities and microbial metabolites.

Hermetia illucens larvae showcases remarkable bioremediation capabilities for both antibiotics and heavy metal contaminants. However, the distinctions in larval intestinal microbiota arising from the single and combined effects of antibiotics and heavy metals remain poorly elucidated. In this study, we delved into the details of larval intestinal bacterial communities and microbial metabolites when exposed to single and combined contaminants of oxytetracycline (OTC) and hexavalent chromium (Cr(VI)). After conversion, single contaminant-spiked substrate showed 75.5% of OTC degradation and 95.2% of Cr(VI) reductiuon, while combined contaminant-spiked substrate exhibited 71.3% of OTC degradation and 93.4% of Cr(VI) reductiuon. Single and combined effects led to differences in intestinal bacterial communities, mainly reflected in the genera of Enterococcus, Pseudogracilibacillus, Gracilibacillus, Wohlfahrtiimonas, Sporosarcina, Lysinibacillus, and Myroide. Moreover, these effects also induced differences across various categories of microbial metabolites, which categorized into amino acid and its metabolites, benzene and substituted derivatives, carbohydrates and its metabolites, heterocyclic compounds, hormones and hormone-related compounds, nucleotide and its metabolites, and organic acid and its derivatives. In particular, the differences induced OTC was greater than that of Cr(VI), and combined effects increased the complexity of microbial metabolism compared to that of single contaminant. Correlation analysis indicated that the bacterial genera, Preudogracilibacillus, Enterococcus, Sporosarcina, Lysinibacillus, Wohlfahrtiimonas, Ignatzschineria, and Fusobacterium exhibited significant correlation with significant differential metabolites, these might be used as indicators for the resistance and bioremediation of OTC and Cr(VI) contaminants. These findings are conducive to further understanding that the metabolism of intestinal microbiota determines the resistance of Hermetia illucens to antibiotics and heavy metals.

Drivers of genomic diversity and phenotypic development in early phases of domestication in Hermetia illucens.

The black soldier fly (BSF), Hermetia illucens, has the ability to efficiently bioremediate organic waste into usable bio-compounds. Understanding the impact of domestication and mass rearing on fitness and production traits is therefore important for sustainable production. This study aimed to assess patterns of genomic diversity and its association to phenotypic development across early generations of mass rearing under two selection strategies: selection for greater larval mass (SEL lines) and no direct artificial selection (NS lines). Genome-wide single nucleotide polymorphism (SNP) data were generated using 2bRAD sequencing, while phenotypic traits relating to production and population fitness were measured. Declining patterns of genomic diversity were observed across three generations of captive breeding, with the lowest diversity recorded for the F3 generation of both selection lines, most likely due to founder effects. The SEL cohort displayed statistically significantly greater larval weight com the NS lines with pronounced genetic and phenotypic directional changes across generations. Furthermore, lower genetic and phenotypic diversity, particularly for fitness traits, were evident for SEL lines, illustrating the trade-off between selecting for mass and the resulting decline in population fitness. SNP-based heritability was significant for growth, but was low or non-significant for fitness traits. Genotype-phenotype correlations were observed for traits, but individual locus effect sizes where small and very few of these loci demonstrated a signature for selection. Pronounced genetic drift, due to small effective population sizes, is likely overshadowing the impacts of selection on genomic diversity and consequently phenotypic development. The results hold particular relevance for genetic management and selective breeding for BSF in future.

The underlying mechanisms of oxytetracycline degradation mediated by gut microbial proteins and metabolites in Hermetia illucens.

Hermetia illucens larvae can enhance the degradation of oxytetracycline (OTC) through its biotransformation. However, the underlying mechanisms mediated by gut metabolites and proteins are unclear. To gain further insights, the kinetics of OTC degradation, the functional structures of gut bacterial communities, proteins, and metabolites were investigated. An availability-adjusted first-order model effectively evaluated OTC degradation kinetics, with degradation half-lives of 4.18 and 21.71 days for OTC degradation with and without larval biotransformation, respectively. Dominant bacteria in the larval guts were Enterococcus, Psychrobacter, Providencia, Myroides, Enterobacteriaceae, and Lactobacillales. OTC exposure led to significant differential expression of proteins, with functional classification revealing involvement in digestion, transformation, and adaptability to environmental stress. Upregulated proteins, such as aromatic ring hydroxylase, acted as oxidoreductases modifying the chemical structure of OTC. Unique metabolites, aclarubicin and sancycline identified were possible OTC metabolic intermediates. Correlation analysis revealed significant interdependence between gut bacteria, metabolites, and proteins. These findings reveal a synergistic mechanism involving gut microbial metabolism and enzyme structure that drives the rapid degradation of OTC and facilitates the engineering applications of bioremediation.

Changes in physicochemical, structural and functional properties, and lysinoalanine formation during the unfolding and refolding of pH-shifted black soldier fly larvae albumin.

The changes of physicochemical, structural and functional properties and the lysinoalanine (LAL) formation during the unfolding and refolding of black soldier fly larvae albumin (BSFLA) induced by acid/alkaline pH shift were explored. The results showed that acid/alkaline conditions induced unfolding of BSFLA structure, but also accompanied by the formation of some large aggregates due to the hydrophobic interactions, hydrogen bonds, and disulfide bonds. Compared with control or pH1.5 shift, pH12 shift treatment significantly increased the electrostatic repulsion, surface hydrophobicity, free sulfhydryl group, and deamidation reactions, but reduced the fluorescence intensity of BSFLA, and these change in protein conformation contributed to increase in solubility, emulsion activity, and emulsion stability. But the content of LAL in BSFLA was increased by 93.39 % by pH 12 shift treatment. In addition, pH1.5 shift modified BSFLA tended to form ß-sheet structure through unfolding and refolding, resulting in the formation of aggregates with larger particle sizes, and reducing the solubility and the LAL content by 7.93 % and 65.53 %, respectively. SDS-PAGE profile showed that pH12/1.5 shifting did not cause irreversible denaturation of protein molecules. Therefore, pH12-shift is good way to improve the functional properties of BSFLA, but the content of LAL should be reduced to make it better used in food.

Biosafety assessment of laying hens fed different treatments of black soldier flies (Hermetia illucens) under doxycycline stress.

The black soldier fly (BSF, Hermetia illucens) is a resource insect that can utilize livestock and poultry feces. However, BSFs may also increase the risk of transmission of antibiotic resistance genes (AGRs) that are widespread in livestock and poultry farm environments. Therefore, we aimed to evaluate the biosecurity risks of different BSF treatments in the laying chicken food chain using the "chicken manure-BSF-laying hens" model. Our results indicated that different BSF treatments significantly affected antibiotic residue, ARGs, MGEs, bacterial antibiotic resistance, and bacterial microbial community composition in the food chain of laying hens fed BSFs. These risks can be effectively reduced through starvation treatment and high-temperature grinding treatment. Comprehensive risk assessment analysis revealed that starvation combined with high-temperature milling (Group H) had the greatest effect.

Effects of Defatted and Hydrolyzed Black Soldier Fly Larvae Meal as an Alternative Fish Meal in Weaning Pigs.

In Experiment 1, a total of eighteen crossbred ([Landrace × Yorkshire] × Duroc) barrows with an initial body weight of 6.74 ± 0.68 kg were randomly divided into three dietary treatments (one pig per cage and six replicates per treatment) and housed in metabolic cages that were equipped with a feeder and slatted floor to collect urine and feces. In Experiment 2, a total of 96 crossbred ([Landrace × Yorkshire] × Duroc) barrows with an initial body weight of 8.25 ± 0.42 kg were used in the 6-week trial. The pigs were randomly divided into three dietary treatments (three pigs per pen and eight replicates per treatment). In Experiment 1, nutrient composition of defatted black soldier fly larvae meal (BLM) was superior to that of hydrolyzed BLM but lower than that of fish meal (FM). Also, defatted BLM and FM had better apparent total track digestibility (ATTD) of crude protein (CP) and better nitrogen retention (p < 0.05) than hydrolyzed BLM, but there was no significant difference (p > 0.05) between defatted BLM and FM. In Experiment 2, defatted BLM improved (p < 0.05) average daily gain (ADG), feed conversion ratio (FCR), and feed cost per kg gain (FCG) compared with FM. Defatted BLM could replace soybean meal and fish meal as an alternative protein source for weaning pigs.

Whole-genome sequencing of two captive black soldier fly populations: Implications for commercial production.

Black soldier fly (BSF; Hermetia illucens) is a promising insect species for food and feed production as its larvae can convert different organic waste to high-value protein. Selective breeding is one way to optimize production, but the potential of breeding is only starting to be explored and not yet utilized for BSF. To assist in monitoring a captive population and implementing a breeding program, genomics tools are imperative. We conducted whole genome sequencing of two captive populations separated by geographical distance - Denmark (DK) and Texas, USA (TX). Various population genetics analyses revealed a moderate genetic differentiation between two populations. Moreover, we observed higher inbreeding in the DK population, and the detection of a subpopulation within DK population aligned well with the recent foundation of the DK population from two captive populations. Additionally, we generated gene ontology annotation and variants annotation for wider potential applications. Our findings establish a robust marker set for research in population genetics, facilitating the monitoring of inbreeding and laying the groundwork for practical breeding programs for BSF.

Effects of black soldier fly larvae (Hermetia illucens L.) as feed supplements on muscle nutrient composition, meat quality, and antioxidant capacity in Qianbei goat.

Objective: Black soldier fly (BSF) as an animal protein feed source is currently becoming a research hot topic. This study investigated the effects of the BSF as a protein feed source for goats on slaughter performance, muscle nutrient composition, amino acids, fatty acids, minerals, and antioxidant levels. Methods: Thirty Qianbei Ma goats (20.30 ± 1.09 kg) were randomly divided into three groups: the control group (GRPC) supplemented with 10% full-fat soybean, treatment 1 (GRPU) supplemented with 10% untreated BSF, and treatment 2 (GRPT) supplemented with 10% heat-treated BSF. One-way ANOVA among groups (with Fisher's least significant difference (LSD) post hoc comparison) was used in this study. Results: The nutrients, amino acids, fatty acids, minerals, and antioxidants in muscle were analyzed. The results showed that there were no significant differences in the moisture, dry matter (DM), crude protein (CP), ash, amino acids, and mineral content of the muscles among the three feeding groups. The slaughter rate and carcass weight of the GRPU and GRPT groups were significantly lower (p<0.05). The overall meat quality of the GRPU and GRPT groups decreased (p<0.05). The individual unsaturated fatty acids and total unsaturated fatty acids in the GRPU group were higher (p<0.05) than those in the GRPC and GRPT groups. Both GRPU and GRPT decreased (p<0.05) the antioxidant capacity of the meat. Conclusion: Therefore, the heat-treated BSF had a better effect on meat quality compared to untreated BSF, but there were greater negative effects on the meat quality of GRPU and GRPT than GRPC.

A cell line derived from the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae).

Insect cell lines are effective tools used in industry and academia. For example, they are used in screening potential insecticides, in making certain proteins for biomedical applications, and in basic research into insect biology. So far, there are no cell lines derived from the black soldier fly, Hermetia illucens (BSF). This may become an issue because BSFs are employed in a range of industrial and household processes. BSFs are used in producing biodiesel, in developing cosmetics and skin creams, and in the production of some medicines and animal feeds. BSF larvae process waste streams from a variety of sources into food for some animals and are also used in household composting. Our BSF cell line, designated BCIRL-HiE0122021-SGS, was developed from eggs using the medium CLG#2 (50% L-15 + 50% EX-CELL 420, with 9% FBS and antibiotics), with many other media being tested. This cell line consists of attached cells with a variety of morphologies and its identity was authenticated using CO1 barcoding. A growth curve was generated and the resulting doubling time was 118 h. We quantified the fatty acid methyl esters (FAMES) and recorded the expected range of saturated, monounsaturated, and polyunsaturated FAMEs, with only trace levels of lauric acid being noted. The BSF cell line is available free of charge by request.

Biogas Digestate and Sewage Sludge as Suitable Feeds for Black Soldier Fly (Hermetia illucens) Larvae.

Hermetia illucens larvae can use organic wastes as a substrate, which makes them an interesting potential feed. However, waste may contain heavy metals, which are limited in feed. Here, we investigated the ability of H. illucens to grow on organic wastes and measured their heavy metal bioaccumulation. The larvae were fed with food waste, biogas digestates, and sewage sludge. When the first adult fly was visible, the tests were stopped and the larvae immediately processed. The samples (wastes before use, larvae after feeding) were analysed for mineral nutrient and heavy metal content using AAS and ICP-OES, respectively. The results show that the weight of the larvae fed with food waste increased sevenfold, which was broadly in line with expectations. Those fed with sewage sludge and digestate from biogas station increased threefold. While the larvae fed with sewage sludge exceeded the limits for heavy metals, particularly Cd and Pb, in feedstock, those fed with biogas digestate and food waste did not. These findings add to the literature showing the suitability of different wastes as H. illucens feed, and the importance of excluding waste contaminated with heavy metals from larvae intended for use as animal feed, or else diverting these larvae to non-feed uses.

Model-based process optimization of black soldier fly egg production.

Black soldier fly (BSF) larvae (Hermetia illucens) serve as a valuable protein source for animal feed. Limiting factors in the industrial rearing of BSF are the reproduction process and egg output. Studies indicate the potential to shorten preoviposition time and increase egg output through better utilization of environmental variables, such as temperature and light, in industrial settings. Excessive stimulation, however, can lead to stress, elevated production costs, and reduced egg numbers, emphasizing the need for a delicate balance. This study addresses these challenges by investigating controlled manipulation of environmental variables to stimulate mating and enhance egg production, thereby developing a comprehensive model encompassing the adult fly life cycle, mating, and egg production. Model parameters were fitted using literature data, and the model's plausibility was tested through simulations. Using the model and optimal control methods, the calculated dynamic trajectories for environmental variables when compared to the standard approach in a constant environment demonstrated higher output and shorter production cycles at reasonable energy costs. Applications for this model-based optimization are demonstrated for various scenarios, highlighting the practical utility and versatility of the developed model. This study contributes valuable insights for improving rearing practices of BSF through environmental stimulation, offering potential advancements in egg production efficiency and overall sustainability.