Sequential Extraction and Characterisation of Lipids, Proteins, and Chitin from Black Soldier Fly (Hermetia illucens) Larvae, Prepupae, and Pupae

Abstract

Over the past years, several insect species have gained increased attention as feedstock for food, feed, and industrial applications. One such species is Hermetia illucens, whose larvae can convert low-value organic waste into valuable fat-and protein-rich biomass. Previous research on extracting their lipids, proteins, and chitin has repeatedly focused on one life stage, while in practice different life stages coexist in the same rearing batch. In this study, the feasibility of the sequential extraction of said components from the larval, prepupal, and pupal stage of H. illucens was investigated. Additionally, the chemical composition of the life stages and their extracts was analysed. Following the lipid extraction with petroleum ether, insect proteins were extracted via solubilisation at pH 11.0 and precipitation at pH 4.0. This procedure delivered protein recoveries ranging between 27-57 % for the three life stages, with the extracts having high protein contents (85-98 %). After protein extraction, the residual impure chitin was treated sequentially with HCl and NaOH for further purification. No residual amino acids were detected by UPLC analysis of the purified chitin, which showed acetylation degrees of ± 90 %. Overall, it was concluded that the extraction procedure is indeed suitable for all investigated life stages of H. illucens, allowing for the extraction high-value biomolecules for use in industrial applications.

Insect Fat in Animal Nutrition – A Review

“…The most abundant insect unsaturated fatty acids (UFAs) are oleic acid (C18:1 cis 9) and linoleic acid (C18:2 cis 9,12) (Paul et al, 2017;Rumpold and Schlüter, 2013;Sosa and Fogliano, 2017). However, as we mentioned previously, FA content and composition strongly depend on insect species and stage of development (Paul et al 2017;Smets et al, 2020). Only a few insect lipids are solid at room temperature and are thus called insect fats.…”

“…However, the nutrients profile of the H. illucens varied during different stages of the life cycle (it increased from 4.8% of DM on the first day of larval age to 28.4% of DM on the 14 th day of age) and was also influenced by the rearing substrate (Liu et al, 2017, Smets et al, 2020.…”

Full-Fat Insect Meal as a Protein and Energy Source for Weaned Piglets: Effects on Growth Performance, Nutrient Digestibility, Gastrointestinal Function and Microbiota

“…This polysaccharide is the major component of the insect's cuticle and creates a strong skeleton together with minerals and proteins. The exoskeleton of insects is different from crustaceans by having more amino acids strongly bound to the chitin [39,40] and the degree of chitin deacetylation is dependent on the insect life stage [41]. Inclusion of chito-oligosaccharide (derivates from chitosan) in a corn-soybean meal diet has been shown to reduce the incidences and score of diarrhea in piglets weaned at 16 days of age [42], and in piglets weaned at 21 days of age and challenged with Escherichia coli [43].…”

Larvae Mediated Valorization of Industrial, Agriculture and Food Wastes: Biorefinery Concept through Bioconversion, Processes, Procedures, and Products

“…The results suggested that pH had a significant effect on lipid separation [34], which is vital in wet mode fractionation. Lipids, proteins and chitin were sequentially extracted from the larvae, prepupae and pupae of BSFs with a standard procedure, which proves the feasibility of obtaining valuable biomolecules from BSFs of different life stages reared on low-value organic waste streams with different composition [35]. Systematic approaches for the extraction and fractionation of proteins, lipids, and chitin from BSF prepupa were proposed [30].…”

“…The protein solubility curve for BSF at different life stages as a function of pH was elucidated and the maximum protein solubility for all samples appeared in the basic range of 10 to 12. The isoelectric pH for precipitation of solubilized protein in alkaline medium was identified within the pH range of pH 4-4.5 [35]. The possible explanation for the limited overall yield of protein from BSFL when compared to other insects like Tenebrio molitor and Acheta domesticus could be the presence of insoluble proteins in the matrix.…”