Chitin from chicken bones and feet: reality or confusion? A brief analysis of the current situation

Abstract

The search for inexpensive raw materials for chitin production has led to the exploration of various natural resources, including some less conventional ones, such as plants and waste from the processing of various animals. In this context, the production of chitin from chicken bones and feet has been reported, attracting attention as a cheap and widely available source in some regions. However, to the best of our knowledge, birds do not possess genes that encode chitin synthases, the enzymes responsible for chitin biosynthesis. Therefore, this study analyzes the results reported in related articles, especially their FTIR spectra, to assess when the obtained material can be identified as chitin. The analysis revealed that, in some cases, there is poor agreement between the signals in these spectra and the characteristic signals established for well-characterized chitins, while in others, the spectra exhibit signals with a high noise-to-signal ratio that limits their use for identification. Furthermore, the X-ray diffraction studies reported in some of these works provide scarce support to confirm the presence of chitin in these materials. A search of two specialized databases confirmed that, to date, no results have been reported for genes expressing chitin synthases in birds. Finally, some recommendations are offered for properly addressing the studies necessary for the unambiguous identification of these materials.

Keywords

raw materials / chitin synthases / FTIR spectra / Gallus gallus / N-acetylglucosamine

References

[1] Secher A. Travels with Trilobites: Adventures in the Paleozoic. New York: Columbia University Press; 2022.

[2] Lárez-Velásquez C, López F. Chito-oligosaccharides: A mini-review on sources, production, and agricultural applications. Adv Mod Agric. 2024; 5: 2730.

[3] Wasule DL, Shinde RM. Versatile Applications of Chitosan and Its Derivatives Across Diverse Industries. Biopolymers. 2026; 117: e70073.

[4] Wu CC, Lai N, Chen BY, Hsueh CC. Feasibility study of chitosan extraction from waste leaves of Luffa cylindrica for bioresource recycling . Sust Chem Pharm. 2022; 30: 100864.

[5] Yahcob-Saddalani S, Pansacala J, Fernando J, Toledo R. Chitin extraction from sardine fish scales. Int J Biosci. 2022; 21: 5, 216-222.

[6] Jalal AF, Risheed CM, Ibrahim BM. Optimization of Chitin Extraction from Chicken Feet. J Anal Bioanal Techniques. 2012; 03: 05.

[7] Zaeed NA, Issa N, Karabet F. Preparation and characterization of chitosan from chicken feet. Am J Research. 2017; 4: 26-41.

[8] Muhsin ZAA, Aldhamin AS, Shafik SS. Chicken Bone as Chitin Source. J Univ Shanghai Sci Technol. 2021; 23: 238-44.

[9] Muhsin ZAA, Aldhamin AS, Shafik SS. Chitin Preparation and Characterization from Chicken Bone. Eco Env Cons. 2021; 27: S150-6.

[10] National Center for Biotechnology Information - Gene database (NCBI Gene) [Internet]. National Library of Medicine; [cited 2026 Jan 19]. Available from: https://www.ncbi.nlm.nih.gov/gene/

[11] Genome Browser Gateway [Internet]. Genome Institute of the University of California, Santa Cruz; [cited 2026 Feb 13]. Available from: https://ucsc.crg.eu/cgi-bin/hgGateway

[12] Holen MM, Vaaje-Kolstad G, Kent MP, Sandve SR. Gene family expansion and functional diversification of chitinase and chitin synthase genes in Atlantic salmon (Salmo salar) . G3 (Bethesda). 2023; 13: jkad069.

[13] Stern R. Go Fly a Chitin: The Mystery of Chitin and Chitinases in Vertebrate Tissues. Front Biosci (Landmark Ed). 2017; 22: 580-95.

[14] Weigel PH, West CM, Zhao P, Wells L, Baggenstoss BA, Washburn JL. Hyaluronan synthase assembles chitin oligomers with -GlcNAc(α1→)UDP at the reducing end. Glycobiology. 2015; 25: 632-43.

[15] DeAngelis PL, Zimmer J. Hyaluronan synthases; mechanisms, myths, & mysteries of three types of unique bifunctional glycosyltransferases. Glycobiology. 2023; 33: 1117-27.

[16] Sargent TD, Dawid IB. Differential gene expression in the gastrula of Xenopus laevis . Science. 1983; 222: 135-9.

[17] Bulawa CE. CSD2, CSD3, and CSD4, genes required for chitin synthesis in Saccharomyces cerevisiae: the CSD2 gene product is related to chitin synthases and to developmentally regulated proteins in Rhizobium species and Xenopus laevis . Mol Cell Biol. 1992; 12: 1764-76.

[18] Atkinson EM, Long SR. Homology of Rhizobium meliloti NodC to polysaccharide polymerizing enzymes . Mol Plant Microbe Interact. 1992; 5: 439-42.

[19] Cárdenas G, Cabrera G, Taboada E, Miranda SP. Chitin characterization by SEM, FTIR, XRD, and 13C cross polarization/mass angle spinning NMR. J App Polym Sci. 2004; 93: 1876-85.

[20] Hajji S, Younes I, Ghorbel-Bellaaj O, Hajji R, Rinaudo M, Nasri M, et al. Structural differences between chitin and chitosan extracted from three different marine sources. Int J Biol Macromol. 2014; 65: 298-306.

[21] Ibitoye EB, Lokman IH, Hezmee MNM, Goh YM, Zuki ABZ, Jimoh AA. Extraction and physicochemical characterization of chitin and chitosan isolated from house cricket. Biomed Mater. 2018; 13: 025009.

[22] Kaya M, Sofi K, Sargin I, Mujtaba M. Changes in physicochemical properties of chitin at developmental stages (larvae, pupa and adult) of Vespa crabro (wasp) . Carbohydr Polym. 2016; 145: 64-70.

[23] Kaya M, Baran T, Asan-Ozusaglam M, Cakmak YS, Tozak KO, Mol A, et al. Extraction and characterization of chitin and chitosan with antimicrobial and antioxidant activities from cosmopolitan Orthoptera species (Insecta). Biotechnol Bioproc Eng. 2015; 20: 168-79.

[24] Daraghmeh NH, Chowdhry BZ, Leharne SA, Al Omari MM, Badwan AA. Chitin. In: Brittain HG, editor. Profiles of Drug Substances, Excipients and Related Methodology, Vol. 36. Burlington: Academic Press; 2011. pp. 35-102.

[25] Aouadi A, Saoud DH, Laouini SE, Rebiai A, Achouri A, Mohammed HA, et al. Synergistic chitin-zinc nanocomposites from shrimp shell waste: characterization, antioxidant, and antibacterial properties. Biomass Conv Biorefin. 2025; 15: 545-61.

[26] Focher B, Naggi A, Torri G, Cosani A, Terbojevich M. Structural differences between chitin polymorphs and their precipitates from solutions-evidence from CP-MAS 13C-NMR, FT-IR and FT-Raman spectroscopy. Carbohydr Polym. 1992; 17: 97-102.

[27] Psarianos M, Rossi G, Van Der Borght M, Schlüter OK. Methods for estimating the chitin content of edible insects: Advantages and challenges. Carbohydr Polym. 2025; 367: 124009.

[28] Cardozo FA, Facchinatto WM, Colnago LA, Campana-Filho SP, Pessoa A. Bioproduction of N-acetylglucosamine from colloidal α-chitin using an enzyme cocktail produced by Aeromonas caviae CHZ306 . World J Microbiol Biotechnol. 2019; 35: 114.

[29] Kumirska J, Czerwicka M, Kaczyński Z, Bychowska A, Brzozowski K, Thöming J, et al. Application of spectroscopic methods for structural analysis of chitin and chitosan. Mar Drugs. 2010; 8: 1567-636.

[30] Hemmami H, Zeghoud S, Amor IB, Ahmed S. Chitin and chitosan characterization: spectroscopic methods. In: Ahmed S, Zeghoud S, Hemmami H, Amor IB, editors. Chitin and Chitosan: Physical and Chemical Properties. Singapore: Jenny Stanford Publishing Pte. Ltd; 2025. pp. 221-54.

[31] Cabib E, Sburlati A. Enzymatic determination of chitin. Methods Enzymol. 1988; 161; 457-9.

[32] Brugnerotto J, Lizardi J, Goycoolea FM, Argüelles-Monal W, Desbrières J, Rinaudo M. An infrared investigation in relation with chitin and chitosan characterization. Polymer. 2001; 42: 3569-80.

[33] Garnjanagoonchorn W, Wongekalak L, Engkagul A. Determination of chondroitin sulfate from different sources of cartilage. Chem Eng Process: Process Intensif. 2007; 46: 465-71.

[34] de Oliveira SA, da Silva BC, Riegel-Vidotti IC, Urbano A, de Sousa Faria-Tischer PC, Tischer CA. Production and characterization of bacterial cellulose membranes with hyaluronic acid from chicken comb. Int J Biol Macromol. 2017; 97: 642-53.