Isolation of Chitin from Black Soldier Fly (Hermetia illucens) and Its Usage to Metal Sorption

Turning black soldier fly rearing by-products into valuable materials: Valorisation through chitin and chitin nanocrystals production

The industry of insect-based proteins as feed and food products has been encountering a huge development since the last decade, and industrial-scale factories are now arising worldwide. Among all the species studied, Black Soldier Fly is one of the most promising and farmed. This rearing activity generates several by-products in the form of chitin-rich biomass that can be valorised to keep a virtuous production cycle embedded in the scope of the bioeconomy. Herein, we report the isolation of chitin and, for the first time, chitin nanocrystals (ChNCs) from all the BSF rearing by-products, i.e., moults (larval exuviae, puparium) and dead adults. Extraction yields, were dependent on the type of by-products and ranged from 5.8 % to 20.0 %, and the chemical structure of the extracts exhibited typical features of α-chitin, confirmed by FTIR, NMR, XRD and TGA analysis. Both STEM in SEM and AFM analysis confirmed the isolation of chitin nanocrystals presenting a rod-like morphology. The average nanocrystal height estimated by AFM ranged from 13 to 27 nm depending on the by-product sample. The following results highlighted the potential of BSF rearing by-products, promoting an approach to valorise those industrial waste and paving the way towards insect-based biorefinery.

Necrophages and necrophiles: a review of their antibacterial defenses and biotechnological potential

With antibiotic resistance on the rise, there is an urgent need for new antibacterial drugs and products to treat or prevent infection. Many such products in current use, for example human and veterinary antibiotics and antimicrobial food preservatives, were discovered and developed from nature. Natural selection acts on all living organisms and the presence of bacterial competitors or pathogens in an environment can favor the evolution of antibacterial adaptations. In this review, we ask if vultures, blow flies and other carrion users might be a good starting point for antibacterial discovery based on the selection pressure they are under from bacterial disease. Dietary details are catalogued for over 600 of these species, bacterial pathogens associated with the diets are described, and an overview of the antibacterial defenses contributing to disease protection is given. Biotechnological applications for these defenses are then discussed, together with challenges facing developers and possible solutions. Examples include use of (a) the antimicrobial peptide (AMP) gene sarcotoxin IA to improve crop resistance to bacterial disease, (b) peptide antibiotics such as serrawettin W2 as antibacterial drug leads, (c) lectins for targeted drug delivery, (d) bioconversion-generated chitin as an antibacterial biomaterial, (e) bacteriocins as antibacterial food preservatives and (f) mutualistic microbiota bacteria as alternatives to antibiotics in animal feed. We show that carrion users encounter a diverse range of bacterial pathogens through their diets and interactions, have evolved many antibacterial defenses, and are a promising source of genes, molecules, and microbes for medical, agricultural, and food industry product development.

Mealworm larvae and black soldier fly larvae as novel protein supplements for cattle consuming low-quality forage

The global population is projected to increase, indicating that there will be greater demand for animal protein to meet the associated food needs. This demand will place additional pressure on livestock systems to increase output while also minimizing natural resource inputs. Insect protein has emerged as a potential alternative to conventional protein feeds, such as soybean meal. Mealworm larvae (MWL; Tenebrio molitor) have been studied in poultry and swine as an alternative protein source; however, there is no research currently evaluating MWL for cattle. Black soldier fly larvae (BSFL; Hermetia illucens) have also received attention for their potential use in livestock feed due to their scalability and nutritional value, but research in cattle is limited. The objective of this study was to evaluate the effects of whole-dried MWL and defatted BSFL as protein supplements for cattle consuming forage. Five ruminally cannulated steers were utilized in a 5 × 5 Latin square experiment to determine how MWL and BSFL supplementations affect forage utilization. Steers consuming ad libitum low-quality forage (76.5% neutral detergent fiber [NDF], 4.2% crude protein) were provided one of the five treatments each period: 1) control with no supplement (CON), 2) soybean meal (CONV), 3) BSFL, 4) MWL, or 5) 50/50 by-weight blend of BSFL and MWL (MIX). All treatments were provided at 100 mg N/kg BW and periods included 8 d for treatment adaptation, 5 d for intake and digestion, and 1 d for ruminal fermentation measures. Protein supplementation stimulated forage organic matter intake (FOMI; P ≤ 0.01) relative to CON (3.28 kg/d). There was a significant difference in FOMI (P ≤ 0.01) between BSFL (4.30 kg/d) and CONV (4.71 kg/d), but not between CONV and MWL (P = 0.06, 4.43 kg/d). Total digestible OM intake (TDOMI) was also stimulated by the provision of protein (P ≤ 0.01), from 1.94 kg/d for CON to an average of 3.24 kg/d across protein supplements. Organic matter digestibility (OMD) and NDF digestibility (NDFD) were not affected by treatment (P ≥ 0.37), for an average OMD of 66.5% and NDFD of 62.7%. There was also no treatment effect on ruminal volatile fatty acid (P = 0.96) or ammonia-N (P = 0.22) concentrations. These data indicate that MWL may stimulate forage utilization by beef cattle to a greater extent than BSFL, but both are viable protein supplements.

Update on Chitin and Chitosan from Insects: Sources, Production, Characterization, and Biomedical Applications

Insects, renowned for their abundant and renewable biomass, stand at the forefront of biomimicry-inspired research and offer promising alternatives for chitin and chitosan production considering mounting environmental concerns and the inherent limitations of conventional sources. This comprehensive review provides a meticulous exploration of the current state of insect-derived chitin and chitosan, focusing on their sources, production methods, characterization, physical and chemical properties, and emerging biomedical applications. Abundant insect sources of chitin and chitosan, from the Lepidoptera, Coleoptera, Orthoptera, Hymenoptera, Diptera, Hemiptera, Dictyoptera, Odonata, and Ephemeroptera orders, were comprehensively summarized. A variety of characterization techniques, including spectroscopy, chromatography, and microscopy, were used to reveal their physical and chemical properties like molecular weight, degree of deacetylation, and crystallinity, laying a solid foundation for their wide application, especially for the biomimetic design process. The examination of insect-derived chitin and chitosan extends into a wide realm of biomedical applications, highlighting their unique advantages in wound healing, tissue engineering, drug delivery, and antimicrobial therapies. Their intrinsic biocompatibility and antimicrobial properties position them as promising candidates for innovative solutions in diverse medical interventions.

A novel chitinous nanoparticles prepared and characterized with black soldier fly (Hermetia illucens L.) using steam flash explosion treatment

This is the first report of the use of steam flash explosion (SFE) to prepare chitinous nanoparticles from black soldier fly (BSF). SFE treatment was performed at a steam pressure of 0.45 to 1.60 MPa with a holding time of 60 s. As the pressure increased, the particle size of the chitinous particles decreased. Under SFE at 1.60 MPa, chitinous nanoparticles with sizes ranging from 59 to 162 nm were produced. SEM, AFM, Raman spectroscopy, FT-IR spectroscopy, ¹H NMR, TGA, and DSC were used to characterize the BSF chitin materials. It was demonstrated that SFE treatment deacetylated chitin to obtain chitosan with 91.24 % deacetylation. In addition, the polymer backbone was maintained, and the degree of polymerization of chitosan nanoparticles was reduced. The activity of the cationic groups of chitosan nanoparticles was improved, thereby enhancing the temperature sensitivity of the polymeric material. It can be concluded that the SFE one-step processing method is a simple and efficient way to prepare homogeneous biomaterial nanoparticles. This study has implications for the development of chitosan nanomaterials for biomedical applications.

Factors influencing accumulation of Zn, Cu, and Ca in the tissues of spiny-cheek crayfish (Faxonius limosus, Rafinesque, 1817)

Both physicochemical and biological factors affect the degree of metal accumulation in crayfish tissues. The content of metals and correlations between the metal concentrations in different tissues and the total length of crayfish is suitable indicators of contamination of the aquatic environment. The aim of the study was to analyse the effect of age and sex of crayfish on the degree of accumulation of Ca, Cu, and Zn in the muscle and exoskeleton. A total of 100 individuals of the spiny-cheek crayfish (Faxonius limosus, Rafinesque, 1817) were caught from Głowińsk reservoir (Poland) in October 2019 using fyke nets. Metal concentrations were determined in freeze-dried samples of the abdominal muscle, exoskeleton, bottom sediment, and water using atomic absorption spectroscopy (AAS). Here, we show that the highest concentrations of Zn were found in the muscle of 4-year-old females, Cu in 3-year-old males, and Ca in 4-year-old males. Sex was a significant factor affecting the content of Ca in the muscle and Zn in the exoskeleton. Age was a significant factor affecting the content of Zn, Cu, and Ca in the muscle and Zn and Cu in the exoskeleton. The bioconcentration factor (BCF) of Zn and Cu in the muscle and exoskeleton of spiny-cheek crayfish was much higher from water than from sediments, unlike Ca. Furthermore, we found significant correlation for muscle between Zn and total length in 3-year-old females and 4-year-old males and between Cu and TL in 3-year-old males. Analysing the recommended daily intake (RDI) for the investigated minerals confirmed that the consumption of 100 g of spiny-cheek crayfish muscle could meet daily requirement for Zn up to 27.5%, for Ca in 12.4%, and over 100% for Cu. The conducted analyses confirmed that the consumption of crayfish meat was safe for the health of potential consumers in terms of the analysed metal content.

The Variety of Applications of Hermetia illucens in Industrial and Agricultural Areas-Review

Hermetia illucens (Diptera: Stratiomyidae, Linnaeus, 1978), commonly known as the black soldier fly (BSF), is a saprophytic insect, which in recent years has attracted significant attention from both the scientific community and industry. The unrestrained appetite of the larvae, the ability to forage on various organic waste, and the rapid growth and low environmental impact of its breeding has made it one of the insect species bred on an industrial scale, in the hope of producing fodder or other ingredients for various animals. The variety of research related to this insect has shown that feed production is not the only benefit of its use. H. illucens has many features and properties that could be of interest from the point of view of many other industries. Biomass utilization, chitin and chitosan source, biogas, and biodiesel production, entomoremediation, the antimicrobial properties of its peptides, and the fertilizer potential of its wastes, are just some of its potential uses. This review brings together the work of four years of study into H. illucens. It summarizes the current state of knowledge and introduces the characteristics of this insect that may be helpful in managing its breeding, as well as its use in agro-industrial fields. Knowledge gaps and under-studied areas were also highlighted, which could help identify future research directions.

Characterization of chitin and chitosan derived from Hermetia illucens, a further step in a circular economy process

Due to their properties and applications, the growing demand for chitin and chitosan has stimulated the market to find more sustainable alternatives to the current commercial source (crustaceans). Bioconverter insects, such as Hermetia illucens, are the appropriate candidates, as chitin is a side stream of insect farms for feed applications. This is the first report on production and characterization of chitin and chitosan from different biomasses derived from H. illucens, valorizing the overproduced larvae in feed applications, the pupal exuviae and the dead adults. Pupal exuviae are the best biomass, both for chitin and chitosan yields and for their abundance and easy supply from insect farms. Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscope analysis revealed the similarity of insect-derived polymers to commercial ones in terms of purity and structural morphology, and therefore their suitability for industrial and biomedical applications. Its fibrillary nature makes H. illucens chitin suitable for producing fibrous manufacts after conversion to chitin nanofibrils, particularly adults-derived chitin, because of its high crystallinity. A great versatility emerged from the evaluation of the physicochemical properties of chitosan obtained from H. illucens, which presented a lower viscosity-average molecular weight and a high deacetylation degree, fostering its putative antimicrobial properties.

Antimicrobial Activity of Chemically and Biologically Treated Chitosan Prepared from Black Soldier Fly (Hermetia illucens) Pupal Shell Waste

Globally, the broad-spectrum antimicrobial activity of chitin and chitosan has been widely documented. However, very little research attention has focused on chitin and chitosan extracted from black soldier fly pupal exuviae, which are abundantly present as byproducts from insect-farming enterprises. This study presents the first comparative analysis of chemical and biological extraction of chitin and chitosan from BSF pupal exuviae. The antibacterial activity of chitosan was also evaluated. For chemical extraction, demineralization and deproteinization were carried out using 1 M hydrochloric acid at 100 °C for 2 h and 1 M NaOH for 4 h at 100 °C, respectively. Biological chitin extraction was carried out by protease-producing bacteria and lactic-acid-producing bacteria for protein and mineral removal, respectively. The extracted chitin was converted to chitosan via deacetylation using 40% NaOH for 8 h at 100 °C. Chitin characterization was done using FTIR spectroscopy, while the antimicrobial properties were determined using the disc diffusion method. Chemical and biological extraction gave a chitin yield of 10.18% and 11.85%, respectively. A maximum chitosan yield of 6.58% was achieved via chemical treatment. From the FTIR results, biological and chemical chitin showed characteristic chitin peaks at 1650 and 1550 cm⁻¹—wavenumbers corresponding to amide I stretching and amide II bending, respectively. There was significant growth inhibition for Escherichia coli, Bacillus subtilis,Pseudomonas aeruginosa,Staphylococcus aureus, and Candida albicans when subjected to 2.5 and 5% concentrations of chitosan. Our findings demonstrate that chitosan from BSF pupal exuviae could be a promising and novel therapeutic agent for drug development against resistant strains of bacteria.

Yellow Mealworm and Black Soldier Fly Larvae for Feed and Food Production in Europe, with Emphasis on Iceland

Insects are part of the diet of over 2 billion people worldwide; however, insects have not been popular in Europe, neither as food nor as a feed ingredient. This has been changing in recent years, due to increased knowledge regarding the nutritional benefits, the need for novel protein production and the low environmental impact of insects compared to conventional protein production. The purpose of this study is to give an overview of the most popular insects farmed in Europe, yellow mealworm, Tenebrio molitor, and black soldier fly (BSF), Hermetia illucens, together with the main obstacles and risks. A comprehensive literature study was carried out and 27 insect farming companies found listed in Europe were contacted directly. The results show that the insect farming industry is increasing in Europe, and the success of the frontrunners is based on large investments in technology, automation and economy of scale. The interest of venture capital firms is noticeable, covering 90% of the investment costs in some cases. It is concluded that insect farming in Europe is likely to expand rapidly in the coming years, offering new proteins and other valuable products, not only as a feed ingredient, but also for human consumption. European regulations have additionally been rapidly changing, with more freedom towards insects as food and feed. There is an increased knowledge regarding safety concerns of edible insects, and the results indicate that edible insects pose a smaller risk for zoonotic diseases than livestock. However, knowledge regarding risk posed by edible insects is still lacking, but food and feed safety is essential to put products on the European market.