Novel Insights on the Sustainable Wet Mode Fractionation of Black Soldier Fly Larvae (Hermetia illucens) into Lipids, Proteins and Chitin

The black soldier fly larvae (BSFL) is a sustainable ingredient for feed applications, biofuels, composite materials and other biobased products. Processing BSFL to obtain lipid and protein fractions with enhanced functional properties as a suitable replacement for conventional feed ingredients has gained considerable momentum. In this regard, a novel and sustainable wet mode fractionation (WMF) scheme for BSFL was explored. Fresh BSFL were steam blanched and pulped to obtain BSFL juice and juice press cake. Subsequent treatment of BSFL juice employing homogenization or enzyme incubation and further centrifugation resulted in the obtention of four different BSFL fractions (Lipid—LF; Cream—CF; Aqueous—AF; and Solid—SF). Total energy consumption for a batch BSFL (500 g) WMF process was 0.321 kWh. Aqueous and solid fractions were the predominant constituents of BSFL juice. Lauric acid (44.52–49.49%) and linoleic acid (19.12–20.12%) were the primary fatty acids present in BSFL lipids. Lipid hydrolysis was observed in lipids belonging to the solid (free fatty acids > triacylglycerides) and cream fractions. Aqueous fraction proteins (ctrl) displayed superior emulsion stability and foam capacity than other treatments. Juice press cake retained 60% of the total chitin content and the rest, 40%, was found in the solid fraction (ctrl). The material distribution of principal constituents in different fractions of the WMF process and amino acid profile was elucidated. Overall, the versatile WMF process proposed in this study involves simple unit operations to obtain functional ingredients from BSFL, which can be further explored by researchers and industry stakeholders.

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The effect of Rhodococcus rhodochrous supplementation on black soldier fly (Diptera: Stratiomyidae) development, nutrition, and waste conversion

Journal of Insects as Food and Feed ◽

10.3920/jiff2020.0033 ◽

2021 ◽

pp. 1-12

Author(s):

K. Franks ◽

E. Kooienga ◽

M. Sanders ◽

K. Pendarvis ◽

F. Yang ◽

...

Keyword(s):

Fatty Acids ◽

Stress Responses ◽

Muscle Development ◽

Protein Composition ◽

Rhodococcus Rhodochrous ◽

Larval Body ◽

Black Soldier Fly ◽

Black Soldier Fly Larvae ◽

Fly Larvae ◽

Waste Conversion

Black soldier fly larvae are mass produced globally for use as livestock, poultry, and aquaculture feed. Efforts are continuously seeking processes optimising larval rate of growth, size, and waste conversion as a means to lower cost and increase output. Manipulating microbes in the larval substrate (i.e. fermentation or supplementation) has been demonstrated as a potential solution. However, identifying appropriate microbes for use in this process has been limited. The objective of this study was to determine whether supplementing black soldier fly larvae with the oleaginous microbe Rhodococcus rhodochrous would result in accelerated larval development, increased final larval body size, and increased conversion efficiency. Larvae fed a sterile, or non-sterile, diet treated with R. rhodochrous grew 3× faster than the control by the third day and were approximately 2× larger than the control by the conclusion of the experiment. Conversion rate was 2× greater for the treatments indicating less feed would be needed to achieve maximum weight gain. Protein composition of resulting larvae fed diet supplemented with R. rhodochrous, was significantly different than the control not receiving the microbial infusion. Larvae provided the microbe had 4.20 and 2.79% greater fatty acid composition and short-chained fatty acids, respectively, but lower monounsaturated fatty acids (1.60%) and polyunsaturated fatty acids (2.4%). Furthermore, larvae provided R. rhodochrous produced significantly more proteins related to energy production and storage, as well as muscle development and contraction, while those sans microbe, produced proteins related to stress responses (e.g. heat shock proteins). While, this study yielded positive results for the inclusion of R. rhodochrous as part of the black soldier fly larval diet, additional research is needed to optimise the dose at an industrial scale.

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Cottonseed Press Cake as a Potential Diet for Industrially Farmed Black Soldier Fly Larvae Triggers Adaptations of Their Bacterial and Fungal Gut Microbiota

Frontiers in Microbiology ◽

10.3389/fmicb.2021.634503 ◽

2021 ◽

Vol 12 ◽

Author(s):

Dorothee Tegtmeier ◽

Sabine Hurka ◽

Patrick Klüber ◽

Karina Brinkrolf ◽

Philipp Heise ◽

...

Keyword(s):

Gut Microbiome ◽

Production Systems ◽

Press Cake ◽

Amplicon Sequencing ◽

Diet Group ◽

Cotton Production ◽

Black Soldier Fly ◽

Black Soldier Fly Larvae ◽

Fly Larvae ◽

The Impact

Black soldier fly larvae (Hermetia illucens, Diptera: Stratiomyidae) are used for the bioconversion of organic side products into valuable compounds such as proteins, lipids and chitin. However, the economic competitiveness of farmed insects compared to conventional protein production systems in agriculture and aquaculture depends on the availability of large quantities of inexpensive insect feed. Cottonseed press cake (CPC) is a side-stream of cotton production that is rich in proteins and lipids but unsuitable as feed for several farmed animals, except ruminants, due to the presence of the anti-nutritional sesquiterpenoid gossypol. Here, we tested CPC as a feed for black soldier fly larvae and studied the impact of this diet on the gut microbiome. Larvae reared on CPC developed normally and even showed a shorter life-cycle, but were smaller at the end of larval development than control larvae reared on chicken feed. The adaptability of the larvae to different diets is mediated by their versatile gut microbiome, which facilitates digestion and detoxification. We therefore used amplicon sequencing to analyze the bacterial and fungal communities associated with larvae reared on each diet, revealing differences between the larval guts and frass (residual feed substrate) as well as differences between the two diet groups. For example, Actinomycetaceae and Aspergillaceae were significantly enriched in guts of the CPC diet group and may help to metabolize compounds such as gossypol. Potentially probiotic yeasts and beneficial Enterobacteriaceae, which presumably belong to the core microbiota, were detected in high relative abundance in the gut and frass, indicating a functional role of these microbes, especially the protection against pathogens. We conclude that CPC may be suitable as an inexpensive and environmentally sustainable feed for the industrial rearing of black soldier flies.

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Enrichment of polyunsaturated fatty acids in black soldier fly larvae (Hermetia illucens) fortified with squid liver oil

Journal of Insects as Food and Feed ◽

10.3920/jiff2021.0030 ◽

2021 ◽

pp. 1-12

Author(s):

G. Tirtawijaya ◽

J.-S. Choi

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Animal Feed ◽

Control Group ◽

Feed Conversion ◽

Black Soldier Fly ◽

Hermetia Illucens ◽

Growth Increase ◽

Black Soldier Fly Larvae ◽

Fly Larvae

Black soldier fly larvae (BSFL; Hermetia illucens) are known as an alternative feed for livestock, but their lack of polyunsaturated fatty acids (such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) makes it less valuable. To overcome these problems, BSFL substrate (chicken feed) was fortified with squid liver oil (SLO) at five different concentrations (0, 2.5, 5, 10, and 20%). The growth rate, feed conversion, and nutritional content of BSFL were evaluated at day 15 of rearing. Of the five concentrations, SLO 5% showed the highest growth increase (25.82-fold) among the other treatments (20.63-22.98-fold; P<0.05). The fortification of SLO 5% did not result in differences in survival and feed conversion of larvae compared to larvae fed the control substrate. By rearing BSFL in a substrate containing SLO 5%, the lipid content of the larvae was 32% higher than that of larvae fed the control substrate (P<0.05). The accumulation of lipids was faster in the substrate containing SLO 5% (33.20% for 8 days) than in the control substrate (24.36% for 15 days). The control group of BSFL contained no DHA or EPA, but after rearing on the SLO 5% fortified substrate, the larvae contained DHA at an average level of 2.99 g/100 g lipid and EPA was 2.68 g/100 g lipid. Harvested larvae from SLO 5% treatment was within safe levels of Pb, Cd, As, and Hg (840, 370, 860, and 26.7 μg/kg, respectively), under the EU threshold for animal feed. Based on our results, it concluded that BSFL enriched with PUFAs, DHA and EPA can be considered as important nutritional components of animal feed without excessive heavy metals accumulation by feeding SLO in an appropriate amount.

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Dose-Dependent Retention of Omega-3 Fatty Acids by Black Soldier Fly Larvae (Diptera: Stratiomyidae)

Journal of Economic Entomology ◽

10.1093/jee/toaa045 ◽

2020 ◽

Vol 113 (3) ◽

pp. 1221-1226

Author(s):

Patrick Erbland ◽

Andrei Alyokhin ◽

L Brian Perkins ◽

Michael Peterson

Keyword(s):

Fatty Acids ◽

Individual Growth ◽

Dependent Manner ◽

Omega 3 Fatty Acids ◽

Omega 3 ◽

Alpha Linolenic Acid ◽

Black Soldier Fly ◽

Black Soldier Fly Larvae ◽

Fly Larvae ◽

Dose Dependent

Abstract Black soldier fly larvae, Hermetia illucens (L.), are used to convert organic waste streams into insect-based animal feeds. We tested their ability to retain alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) from feeding substrates, which has important implications for their use in aquaculture. When supplementing a chicken feed diet with increasing concentrations of salmon oil (0–42%) over an increasing number of days (0–8), the concentrations of the three omega-3 acids in larvae increased significantly. Larval survival and biomass accumulation were not affected. Supplementing a chicken feed diet with increasing concentrations (0–14%) of Tetraselmis chui Butcher (Chlorodendrales: Chlorodendraceae) microalgae paste also significantly increased ALA and EPA contents of the harvested larvae. However, microalgae also decreased survival, harvested biomass, and individual growth of larvae feeding on the diet with the highest supplement concentration (14%). DHA was not detected in any microalgae diet or subsequent larval tissue samples. All three omega-3 polyunsaturated fatty acids tested in this study were accumulated in dose-dependent manner, with quadratic, and occasionally linear, equations providing the best description of the observed relationships. There were significant negative correlations between several fatty acids, indicating that they may replace one another in living larvae. Our findings confirm that black soldier fly larvae can retain ingested fatty acids and change fatty acid profiles in their tissues accordingly. However, optimizing nutrient content of harvestable larvae is likely to be more complicated than simply enriching their diets with omega-3 fatty acids.

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