Showing papers on "Chitin published in 2018"
TL;DR: In this review, various methods of chitosan extraction will be approached and compared; the importance of a new method of ecological extraction will been emphasized and several chemical modifications have been reported.
413 citations
TL;DR: In this paper, a review of chitin nanocrystals and their potential applications in biomaterial, electrochemistry, energy storage, separation/absorption, catalyst carrier and textile materials is presented.
253 citations
TL;DR: These quaternized β‐chitin derivatives are found to exhibit excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Rhizopus oryzae and imply that these novel polysaccharide‐based materials can be used as dressings for clinical skin regeneration, particularly for infected wounds.
Abstract: Bacterial infection has always been a great threat to public health, and new antimicrobials to combat it are urgently needed. Here, a series of quaternized β-chitin derivatives is prepared simply and homogeneously in an aqueous KOH/urea solution, which is a high-efficiency, energy-saving, and "green" route for the modification of chitin. The mild reaction conditions keep the acetamido groups of β-chitin intact and introduce quaternary ammonium groups on the primary hydroxyl at the C-6 position of the chitin backbone, allowing the quaternized β-chitin derivatives (QCs) to easily form micelles. These QCs are found to exhibit excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Rhizopus oryzae with minimum inhibitory concentrations (MICs) of 8, 12, 60, and 40 µg mL-1 , respectively. As a specific highlight, their inherent outstanding biocompatibility and significant accelerating effects on the healing of uninfected, E. coli-infected, and S. aureus-infected wounds imply that these novel polysaccharide-based materials can be used as dressings for clinical skin regeneration, particularly for infected wounds.
225 citations
TL;DR: The present investigation was undertaken to evaluate the feasibility of applying different extraction protocols, either chemical extractions or enzymatic assisted extraction, to recover pure fat, protein and chitin fractions in black soldier fly prepupae samples.
194 citations
TL;DR: Immune recognition of chitin also involves pattern recognition receptors to activate immune cells to induce cytokine production and creation of an immune network that results in inflammatory and allergic responses.
Abstract: Chitin, a potential allergy-promoting pathogen-associated molecular pattern (PAMP), is a linear polymer composed of N-acetylglucosamine residues which are linked by β-(1,4)-glycosidic bonds. Mammalians are potential hosts for chitin-containing protozoa, fungi, arthropods, and nematodes; however, mammalians themselves do not synthetize chitin and thus it is considered as a potential target for recognition by mammalian immune system. Chitin is sensed primarily in the lungs or gut where it activates a variety of innate (eosinophils, macrophages) and adaptive immune cells (IL-4/IL-13 expressing T helper type-2 lymphocytes). Chitin induces cytokine production, leukocyte recruitment, and alternative macrophage activation. Intranasal or intraperitoneal administration of chitin (varying in size, degree of acetylation and purity) to mice has been applied as a routine approach to investigate chitin’s priming effects on innate and adaptive immunity. Structural chitin present in microorganisms is actively degraded by host true chitinases, including acidic mammalian chitinases and chitotriosidase into smaller fragments that can be sensed by mammalian receptors such as FIBCD1, NKR-P1, and RegIIIc. Immune recognition of chitin also involves pattern recognition receptors, mainly via TLR-2 and Dectin-1, to activate immune cells to induce cytokine production and creation of an immune network that results in inflammatory and allergic responses. In this review, we will focus on various immunological aspects of the interaction between chitin and host immune system such as sensing, interactions with immune cells, chitinases as chitin degrading enzymes, and immunologic applications of chitin.
159 citations
TL;DR: LPMOs are copper-dependent enzymes that, with glycoside hydrolases, participate in the degradation of recalcitrant carbohydrate polymers, and their activity and structural underpinnings provide insights into biological mechanisms of polysaccharide degradation.
Abstract: Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes, which is evidenced by the established and emerging markets for products derived from these natural polymers. In many cases, this is achieved via industrial processes that use enzymes to break down carbohydrates to monomer sugars. One of the major challenges facing large-scale industrial applications utilizing natural carbohydrate polymers is rooted in the fact that naturally occurring forms of starch, cellulose, and chitin can have tightly packed organizations of polymer chains with low hydration levels, giving rise to crystalline structures that are highly recalcitrant to enzymatic degradation. The topic of this review is oxidative cleavage of carbohydrate polymers by lytic polysaccharide mono-oxygenases (LPMOs). LPMOs are copper-dependent enzymes (EC 1.14.99.53−56) that,...
131 citations
TL;DR: Anticancer activity of aquacultural waste of shrimp shells mediated chitosan, which was proved to be good novel pharmaceutical industries showed that microfibril and porous structures of P. monodon exhibited notable higher activity than chitin.
122 citations
TL;DR: itin degradation by the bacterial LPMO chitin-binding protein CBP21 using H2O2 as cosubstrate is provided, indicating that LPMOs have catalytic efficiencies similar to those of peroxygenases.
118 citations
TL;DR: The importance of chitin forms and chit inases in the plant–fungal interactions and their role in persistent and possible biocontrol is discussed.
Abstract: Chitin is the second abundant polysaccharide in the world after cellulose. It is a vital structural component of the fungal cell wall but not for plants. In plants, fungi are recognised through the perception of conserved microbe-associated molecular patterns (MAMPs) to induce MAMP-triggered immunity (MTI). Chitin polymers and their modified form, chitosan, induce host defence responses in both monocotyledons and dicotyledons. The plants' response to chitin, chitosan, and derived oligosaccharides depends on the acetylation degree of these compounds which indicates possible biocontrol regulation of plant immune system. There has also been a considerable amount of recent research aimed at elucidating the roles of chitin hydrolases in fungi and plants as chitinase production in plants is not considered solely as an antifungal resistance mechanism. We discuss the importance of chitin forms and chitinases in the plant-fungal interactions and their role in persistent and possible biocontrol. Abbreviations ET, ethylene; GAP, GTPase-activating protein; GEF, GDP/GTP exchange factor; JA, jasmonic acid; LysM, lysin motif; MAMP, microbe-associated molecular pattern; MTI, MAMP-triggered immunity; NBS, nucleotide-binding site; NBS-LRR, nucleotide-binding site leucine-rich repeats; PM, powdery mildew; PR, pathogenesis-related; RBOH, respiratory burst oxidase homolog; RLK, receptor-like kinase; RLP, receptor-like protein; SA, salicylic acid; TF, transcription factor.
106 citations
TL;DR: The chitin samples were confirmed as α-chitin based on the FT-IR and TGA, and the chitosan samples were amorphous with low degree of crystallinity, resulting in lower radical scavenging and ferric-chelating ability compared to commercial chitOSan.
101 citations
TL;DR: The DES film showed similar properties to the standard film, while the mechanical properties, swelling behavior, and biodegradation of the DES chitin films proved to be similar to standard chitIn films can be used as wound healing resources.
TL;DR: A green and efficient approach based on choline chloride-malic acid, a NADES, was developed for extracting chitin from crustacean shells, and its effectiveness for demineralization and deproteinization was determined.
Abstract: Natural deep eutectic solvents (NADESs) are sustainable, nontoxic, and biodegradable solvents, which are composed of natural primary metabolites. A green and efficient approach based on choline chloride-malic acid, a NADES, was developed for extracting chitin from crustacean shells, and its effectiveness for demineralization and deproteinization was determined. Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to investigate changes in the chemical composition of extracted chitin. The results revealed that most of the minerals and proteins were removed from the shrimp shells by using a NADES with the assistance of microwave irradiation. The quality of the obtained chitin was superior, and it displayed a relative crystallinity of 71%. All of these results were achieved without using harsh chemicals, which can raise environmental issues. This study provides a green and facile approach for chitin production from crustacean shells and reveals the potential of NADESs for applications in the extraction of biopolymers from natural sources.
TL;DR: Deep eutectic solvent prepared from choline chloride and four organic acid were evaluated and it was found that the purity of chitin extracted was related to acid used, which was associated with type of acid and temperature used during the treatment.
TL;DR: The results suggest that the increased disease resistance of tomato fruit after chitin treatment during storage might be attributed to an elicitation of defense response as mentioned above in fruit.
TL;DR: This study provides a first, experimentally supported, atomistic view of the interactions between an LPMO and crystalline chitin, demonstrating that rearrangement of Cu-coordinating water molecules is necessary when binding the substrate and providing a rationale for the experimentally observed C1 oxidative regiospecificity of SmAA10A.
Abstract: Lytic polysaccharide monooxygenases (LPMOs) are major players in biomass conversion, both in Nature and in the biorefining industry. How the monocopper LPMO active site is positioned relative to the crystalline substrate surface to catalyze powerful, but potentially self-destructive, oxidative chemistry is one of the major questions in the field. We have adopted a multidisciplinary approach, combining biochemical, spectroscopic, and molecular modeling methods to study chitin binding by the well-studied LPMO from Serratia marcescens SmAA10A (or CBP21). The orientation of the enzyme on a single-chain substrate was determined by analyzing enzyme cutting patterns. Building on this analysis, molecular dynamics (MD) simulations were performed to study interactions between the LPMO and three different surface topologies of crystalline chitin. The resulting atomistic models showed that most enzyme–substrate interactions involve the polysaccharide chain that is to be cleaved. The models also revealed a constrained...
TL;DR: In this article, two sources (shrimp wastes and fungus biomass) were used to produce chitosan and the chitin was extracted in the nano-form followed by characterization by transmission electron microscopy.
Abstract: Chitosan, bio-polyaminosacharide, is derived from chitin. Two sources (shrimp wastes and fungus biomass) were used to produce chitosan. And then the chitosan was produced in the nano-form followed by characterization by transmission electron microscopy. The images obtained clearly showed that the size of nano-chitosan ranged between 7 and 13 and 3–6 nm with spherical shape for shrimp and fungal sources, respectively. The antimicrobial activities of the tested concentrations of chitosan and nano-chitosan were examined and found to have high activity against the tested pathogens. The evaluation of the toxicity of the tested concentrations of the produced chitosan and its nano-size were performed using brine shrimp and rat bioassay. Toxicity examination of chitosan and their nano derivatives is an essential procedure to assess the possibility of using these concentrations as food ingredient. Nine groups of rats were treated with either chitosan or nano-chitosan of both sources at 100 and 200 mg kg−1 bw. Adding chitosan in the diet of all groups showed no significant changes in both the blood biochemical and oxidative stress parameters when compared with control group. The histopathology of liver, kidney and stomach confirmed the results of the previous parameters. No signs of inflammation, fibrosis or cirrhosis were found in examined organs. It is concluded that chitosan and nano-chitosan of shrimp and Rhizopus stolonifer had high antimicrobial activity and are not toxic in the same time and it can be used as food ingredients.
TL;DR: Recent data concerning the mechanism of action of specific and nonspecific enzymes in the hydrolysis of chitin and chitosan and regarding the application of a large number of different enzymes in chitooligosaccharide production are summarized, as well as information about the disruption of the polysaccharide crystalline structure by accessory proteins.
TL;DR: In this paper, the fabrication of novel lignin/chitin films from a solvent system composed of the ionic liquid 1-butyl-3methylimidazolium acetate and γ-valerolactone as a biosourced cosolvent was presented.
Abstract: This study presents the fabrication of novel lignin/chitin films from a solvent system composed of the ionic liquid 1-butyl-3-methylimidazolium acetate and γ-valerolactone as a biosourced cosolvent. Scanning electron microscopy and attentuated total reflectance Fourier transform infrared spectroscopy confirmed the successful preparation of the lignin/chitin films. The application of lignin/chitin film as an adsorbent for Fe(III) and Cu(II) cation uptake from aqueous solutions is discussed. It was observed that the maximum adsorption capacity for Fe(III) was 84 wt % and for Cu(II) was 22 wt % within 48 h. The lignin/chitin films could be regenerated by desorption of the Fe(III) and Cu(II) ions. Up to 12 and 46 wt %, respectively, could be released within 48 h by directly soaking the metal ion loaded film within water at room temperature. The lignin/chitin film can be considered as a stable and recyclable bioadsorbent material with a high adsorption metal ion capacity for water purification.
TL;DR: The chitin‐TLR2 interaction is highlighted as a potential target for developing novel therapies in chitIn‐related pathologies and fungal disease and to a size‐dependent system of immuno‐modulation that appears conserved in plants and humans.
Abstract: Chitin is the second most abundant polysaccharide in nature and linked to fungal infection and asthma. However, bona fide immune receptors directly binding chitin and signaling immune activation and inflammation have not been clearly identified because polymeric crude chitin with unknown purity and molecular composition has been used. By using defined chitin (N-acetyl-glucosamine) oligomers, we here identify six-subunit-long chitin chains as the smallest immunologically active motif and the innate immune receptor Toll-like receptor (TLR2) as a primary fungal chitin sensor on human and murine immune cells. Chitin oligomers directly bind TLR2 with nanomolar affinity, and this fungal TLR2 ligand shows overlapping and distinct signaling outcomes compared to known mycobacterial TLR2 ligands. Unexpectedly, chitin oligomers composed of five or less subunits are inactive, hinting to a size-dependent system of immuno-modulation that appears conserved in plants and humans. Since blocking of the chitin-TLR2 interaction effectively prevents chitin-mediated inflammation in vitro and in vivo, our study highlights the chitin-TLR2 interaction as a potential target for developing novel therapies in chitin-related pathologies and fungal disease.
TL;DR: Chitin is an essential component of the cell wall of Cryptococcus neoformans conferring structural rigidity and integrity under diverse environmental conditions and further implicates chitosan as being a critical factor for the pathogenesis of C. neo formans.
Abstract: Chitin is an essential component of the cell wall of Cryptococcus neoformans conferring structural rigidity and integrity under diverse environmental conditions. Chitin deacetylase genes encode the enyzmes (chitin deacetylases [Cdas]) that deacetylate chitin, converting it to chitosan. The functional role of chitosan in the fungal cell wall is not well defined, but it is an important virulence determinant of C. neoformans. Mutant strains deficient in chitosan are completely avirulent in a mouse pulmonary infection model. C. neoformans carries genes that encode three Cdas (Cda1, Cda2, and Cda3) that appear to be functionally redundant in cells grown under vegetative conditions. Here we report that C. neoformans Cda1 is the principal Cda responsible for fungal pathogenesis. Point mutations were introduced in the active site of Cda1 to generate strains in which the enzyme activity of Cda1 was abolished without perturbing either its stability or localization. When used to infect CBA/J mice, Cda1 mutant strains produced less chitosan and were attenuated for virulence. We further demonstrate that C. neoformans Cda genes are transcribed differently during a murine infection from what has been measured in vitro. IMPORTANCECryptococcus neoformans is unique among fungal pathogens that cause disease in a mammalian host, as it secretes a polysaccharide capsule that hinders recognition by the host to facilitate its survival and proliferation. Even though it causes serious infections in immunocompromised hosts, reports of infection in hosts that are immunocompetent are on the rise. The cell wall of a fungal pathogen, its synthesis, composition, and pathways of remodelling are attractive therapeutic targets for the development of fungicides. Chitosan, a polysaccharide in the cell wall of C. neoformans is one such target, as it is critical for pathogenesis and absent in the host. The results we present shed light on the importance of one of the chitin deacetylases that synthesize chitosan during infection and further implicates chitosan as being a critical factor for the pathogenesis of C. neoformans.
TL;DR: Production and understanding of how the enzymes generating bioactive chito-oligomers work is essential for their biotechnological application, and paves the way for future work to take advantage of chitinolytic activities.
Abstract: Chitinases are ubiquitous enzymes that have gained a recent biotechnological attention due to their ability to transform biological waste from chitin into valued chito-oligomers with wide agricultural, industrial or medical applications. The biological activity of these molecules is related to their size and acetylation degree. Chitinase Chit42 from Trichoderma harzianum hydrolyses chitin oligomers with a minimal of three N-acetyl-d-glucosamine (GlcNAc) units. Gene chit42 was previously characterized, and according to its sequence, the encoded protein included in the structural Glycoside Hydrolase family GH18. Chit42 was expressed in Pichia pastoris using fed-batch fermentation to about 3 g/L. Protein heterologously expressed showed similar biochemical properties to those expressed by the natural producer (42 kDa, optima pH 5.5–6.5 and 30–40 °C). In addition to hydrolyse colloidal chitin, this enzyme released reducing sugars from commercial chitosan of different sizes and acetylation degrees. Chit42 hydrolysed colloidal chitin at least 10-times more efficiently (defined by the kcat/Km ratio) than any of the assayed chitosan. Production of partially acetylated chitooligosaccharides was confirmed in reaction mixtures using HPAEC-PAD chromatography and mass spectrometry. Masses corresponding to (d-glucosamine)1–8-GlcNAc were identified from the hydrolysis of different substrates. Crystals from Chit42 were grown and the 3D structure determined at 1.8 A resolution, showing the expected folding described for other GH18 chitinases, and a characteristic groove shaped substrate-binding site, able to accommodate at least six sugar units. Detailed structural analysis allows depicting the features of the Chit42 specificity, and explains the chemical nature of the partially acetylated molecules obtained from analysed substrates. Chitinase Chit42 was expressed in a heterologous system to levels never before achieved. The enzyme produced small partially acetylated chitooligosaccharides, which have enormous biotechnological potential in medicine and food. Chit42 3D structure was characterized and analysed. Production and understanding of how the enzymes generating bioactive chito-oligomers work is essential for their biotechnological application, and paves the way for future work to take advantage of chitinolytic activities.
TL;DR: The results indicate that the exuvium and whole body of T. molitor larva may serve as a source of chitin and chitosan for use in domestic animal feed.
Abstract: The purpose of this study was to investigate the production of chitin and chitosan from both the exuvium and whole body of mealworm (Tenebrio molitor) larvae. Chitin from the exuvium and whole body of T. molitor larvae was chemically extracted with acid and alkali solutions to achieve demineralization (DM) and deproteinization (DP), respectively. The average DM (%) and DP (%) on a dry weight (DW) basis was 32.56 and 73.16% from larval exuvium, and 41.68 and 91.53% from whole body, respectively. To obtain chitosan, chitin particles from the exuvium and whole body of T. molitor larva were heated at various temperatures in different concentrations of NaOH. Average chitin yields were 18.01% and 4.92% of DW from the exuvium and whole body, respectively. The relative average yield of chitosan from whole body was 3.65% of DW. On average, over 90% of chitosan derived from whole body was deacetylated. The viscosity of chitosan from whole body was ranged from 48.0 cP to 54.0 cP. The chitin content of dry and wet byproducts from whole body were 17.32% and 16.94% respectively, compared to dry weight. The chitosan contents of byproducts on a DW basis were 14.48% in dry and 13.07% in wet byproduct. These results indicate that the exuvium and whole body of T. molitor larva may serve as a source of chitin and chitosan for use in domestic animal feed.
TL;DR: Analysis of the hydrolysis products revealed that CmChi1 exhibits ex-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities toward N- acetyl chitooligosaccharides and CC substrates, behavior that makes it different from typical reported chitinases.
Abstract: N-acetyl-d-glucosamine (GlcNAc) possesses many bioactivities that have been used widely in many fields. The enzymatic production of GlcNAc is eco-friendly, with high yields and a mild production process compared with the traditional chemical process. Therefore, it is crucial to discover a better chitinase for GlcNAc production from chitin. A novel chitinase gene (Cmchi1) cloned from Chitinolyticbacter meiyuanensis SYBC-H1 and expressed in Escherichia coli BL21(DE3) cells. The recombinant enzyme (CmChi1) contains a glycosyl hydrolase family 18 catalytic module that shows low identity (12–27%) with the corresponding domain of the well-characterized chitinases. CmChi1 was purified with a recovery yield of 89% by colloidal chitin affinity chromatography, whereupon it had a specific activity of up to 15.3 U/mg. CmChi1 had an approximate molecular mass of 70 kDa after the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its optimum activity for colloidal chitin (CC) hydrolysis occurred at pH 5.2 and 50 °C. Furthermore, CmChi1 exhibited kcat/Km values of 7.8 ± 0.11 mL/s/mg and 239.1 ± 2.6 mL/s/μmol toward CC and 4-nitrophenol N,N′-diacetyl-β-d-chitobioside [p-NP-(GlcNAc)2], respectively. Analysis of the hydrolysis products revealed that CmChi1 exhibits exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities toward N-acetyl chitooligosaccharides (N-acetyl CHOS) and CC substrates, behavior that makes it different from typical reported chitinases. As a result, GlcNAc could be produced by hydrolyzing CC using recombinant CmChi1 alone with a yield of nearly 100% and separated simply from the hydrolysate with a high purity of 98%. The hydrolytic properties and good environmental adaptions indicate that CmChi1 has excellent potential in commercial GlcNAc production. This is the first report on exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities from Chitinolyticbacter species.
TL;DR: The results indicate that feeding behavior affects Chia expression levels as well as chitinolytic activity of the enzyme, and determines chitin digestibility in the particular animals.
Abstract: Chitin, a polymer of N-acetyl-D-glucosamine (GlcNAc), functions as a major structural component in chitin-containing organism including crustaceans, insects and fungi. Recently, we reported that acidic chitinase (Chia) is highly expressed in mouse, chicken and pig stomach tissues and that it can digest chitin in the respective gastrointestinal tracts (GIT). In this study, we focus on major livestock and domestic animals and show that the levels of Chia mRNA in their stomach tissues are governed by the feeding behavior. Chia mRNA levels were significantly lower in the bovine (herbivores) and dog (carnivores) stomach than those in mouse, pig and chicken (omnivores). Consistent with the mRNA levels, Chia protein was very low in bovine stomach. In addition, the chitinolytic activity of E. coli-expressed bovine and dog Chia enzymes were moderately but significantly lower compared with those of the omnivorous Chia enzymes. Recombinant bovine and dog Chia enzymes can degrade chitin substrates under the artificial GIT conditions. Furthermore, genomes of some herbivorous animals such as rabbit and guinea pig do not contain functional Chia genes. These results indicate that feeding behavior affects Chia expression levels as well as chitinolytic activity of the enzyme, and determines chitin digestibility in the particular animals.
TL;DR: Results showed that the esterification of chitin with maleic anhydride significantly improved the ultrasound disintegration of chItin fibrils into nanofibers, and crystallinity of the chit in nan ofibers increased with increase in power and time of the ultrasound treatment.
TL;DR: In this article, a novel biological fermentation method was proposed to process chitin powder utilizing the bacteria Chitinolyticbacter meiyuanensis SYBC-H1.
TL;DR: In this paper, a fast and efficient process for the separation of chitin from waste prawn shells using hot glycerol pretreatment is reported, which enables the removal of protein possibly through dehydration and temperature induced fragmentation into low molecular weight water-soluble fragments.
Abstract: A rapid and efficient process for the separation of chitin from waste prawn shells using hot glycerol pretreatment is reported. The pretreatment of waste prawn shell in hot glycerol enables the removal of protein possibly through dehydration and temperature induced fragmentation into low molecular weight water-soluble fragments, which are subsequently removed from the shell matrix by dissolution in water. In contrast, in the industrial process of preparing chitin from crustacean shells, the deproteinization is carried out with hot aqueous sodium hydroxide. The novel pretreatment present here should be applicable to all crustacean shell waste, in principle. Chitin was isolated by two different methods after the pretreatment in glycerol. In one of the methods, the pretreated shells were treated directly with citric acid to remove protein and minerals (mostly as calcium citrate). In the second method, the pretreated shells were ground and rinsed with water to remove protein fragments and part of the minerals...
TL;DR: Complete degradation of shrimp waste by Paenibacillus sp.
TL;DR: According to statistical analysis, ADF-ADL represents a compromise between accuracy and equipment demand and is a suitable method for determining the chitin content of both insects and their residues.
Abstract: There is a growing interest in the use of insects in poultry, swine and aquaculture feed, as well as pet food applications. All insects produce chitin-based exoskeletons. With regard to chitin content, a precise determination in agricultural applications is crucial because it has favorable functional properties, although it is also difficult to digest for some species of livestock. Three measurement methods were compared to determine the most reliable method of chitin content determination in different insects and selected Hermetia illucens products: acid detergent fiber (ADF) provides the fiber content and the acid detergent lignin (ADL) additionally considers the catecholic compounds. Acetyl group measurement relates the acetate content to the chitin content.; Results: Comparing different insect species, the highest chitin value via ADF measurement was determined for the Tenebrio molitor larvae (155 g kg-1 ). Chitin values higher than 200 g kg-1 revealed that H. illucens residues are a much better valuable source of chitin. For the larval exoskeletons, a chitin content for all measurement methods of more than 350 g kg-1 was determined. In general, the ADF measurement is approximately 5% higher than the ADF-ADL and acetyl measurements. ADF-ADL and acetyl group determinations are approximately equivalent measurement methods.; Conclusion: According to statistical analysis, ADF-ADL represents a compromise between accuracy and equipment demand and is a suitable method for determining the chitin content of both insects and their residues. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.
TL;DR: The O2/laccase/TEMPO oxidation caused no decrease in the degree of N-acetylation or the crystallinity of the original chitin based on FTIR and X-ray diffraction data.