Ionic liquid ultrasound-assisted extraction (IL-UAE) for duck feather keratin and in silico evaluation as a potential procollagen n-endopeptidase inhibitor
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Abstract
This research aims to optimize keratin extraction from duck feathers using an eco-friendly ionic liquid-ultrasound-assisted extraction (IL-UAE) method and evaluate its potential applications in tissue engineering. It investigated the effects of deposition pH (1-6), ultrasonication temperature (40-60°C), and time (60-180 min) on extraction yield and physicochemical properties. The results demonstrated the optimal extraction conditions at pH 3, 40°C, and 60 minutes, yielding 82% keratin with a 0.50 mg/mL concentration, while the lowest yield production was found at pH 6 (33%, 0.20 mg/mL). Meanwhile, characterization via FTIR confirmed predominant ?-sheet structures with characteristic peaks at 3250-3300 cm?¹ (N-H/O-H stretching) and 1700-1500 cm?¹ (C=O stretching). SDS-PAGE revealed pure keratin bands (10-15 kDa), while SEM showed layered, porous morphology suitable for biomaterial applications. Thermogravimetric analysis, furthermore, identified three degradation stages occurred at 0-200°C (3.05% loss), 200-400°C (39.37% loss), and 400-700°C (31.13% loss). Amino acid profiling revealed high L-cystine content (153,064.90-156,926.33 mg/kg) with the significant amounts of glycine (63,958.25-64,064.73 mg/kg), L-proline (77,631.16-77,717.42 mg/kg), and L-leucine (59,111.43-59,198.60 mg/kg). In silico molecular docking studies identified leucine as a promising procollagen N-endopeptidase inhibitor (binding energy -5.0 kcal/mol), which controlled the collagen-breaking and forming process. This ability makes keratin potential to be developed as a scaffold for bone tissue regeneration in medical industry.
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Sianita, M. M., Kusumawati, N., Asri, M. T., Dzulkarnain, S. A., Al Hafidl, A. N., Kahfi, A., Nabila, M. A., Setiawan, F., Isyrak, L., & Rahmawati, K. (2025). Ionic liquid ultrasound-assisted extraction (IL-UAE) for duck feather keratin and in silico evaluation as a potential procollagen n-endopeptidase inhibitor. Communications in Science and Technology, 10(1), 75-86. https://doi.org/10.21924/cst.10.1.2025.1669
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References
[1] D. H. Larson, et al., Global Bone Damage Epidemiology: Emerging Trends and Predictive Models, Journal of Bone and Mineral Research, Vol. 39, No. 1, 2024, pp. 45-62.
[2] E. C. Rodriguez-Merchan, Pathophysiology of Bone Trauma: Comprehensive Contemporary Insights, Injury, Vol. 55, No. 1, 2024, pp. 12-25.
[3] E. M. Curtis, et al., Worldwide Bone Damage Epidemiology: Trends, Projections, and Risk Factors, The Lancet Rheumatology, Vol. 6, No. 1, 2024, pp. e45-e60.
[4] J. A. Kanis, et al., Global Trends in Bone Damage Prevalence and Projections: A Comprehensive Analysis, Osteoporosis International, Vol. 35, No. 2, 2024, pp. 267-285.
[5] X. Wang, et al., Advanced 3D Nanofiber Scaffolds in Tissue Engineering: Biomaterial Innovations, Advanced Materials, Vol. 36, No. 12, 2024, pp. 2311456.
[6] H. Chen, et al., Porous 3D Nanofiber Scaffolds: Emerging Strategies in Regenerative Medicine, Nature Biomedical Engineering, Vol. 8, No. 2, 2024, pp. 145-162.
[7] L. Zhang, et al., Advanced 3D Matrix Design for Bone Cell Proliferation and Differentiation, Tissue Engineering Part A, Vol. 30, No. 5-6, 2024, pp. 267-285.
[8] Y. Zhang, et al., Advanced Biomaterials for Tissue Regeneration: Current Progress and Challenges, Advanced Science, Vol. 8, No. 23, 2021, pp. 2101167.
[9] X. Liu, A. L. Miller, J. P. Urban, Engineered Scaffolds for Regenerative Medicine: Advances and Challenges, Nature Reviews Materials, Vol. 8, No. 4, 2023, pp. 215-230.
[10] M. Rodriguez-Garcia, et al., Synergistic Approaches in Combining Natural and Synthetic Biopolymers for Bone Regeneration, Acta Biomaterialia, Vol. 168, 2024, pp. 45-62.
[11] P. Zhao, et al., Non-Toxic Synthetic Biopolymers for Advanced Bone Tissue Engineering, Biomaterials Science, Vol. 11, No. 18, 2023, pp. 6145-6167.
[12] L. Zhang, et al., Comprehensive Analysis of Poly(3-hydroxybutyrate) Properties in Advanced Biomaterial Applications, Biomacromolecules, Vol. 24, No. 7, 2023, pp. 3456-3472.
[13] H. Chen, et al., Keratin-Based Scaffolds for Enhanced Bone Tissue Integration, Acta Biomaterialia, Vol. 165, 2023, pp. 78-95.
[14] X. Liu, et al., Comprehensive Analysis of Keratin Protein Structure and Molecular Characteristics, International Journal of Molecular Sciences, Vol. 25, No. 3, 2024, pp. 1456.
[15] J. Rodriguez-Martinez, et al., Cell Adhesion Motifs in Extracellular Matrix Proteins, Cellular and Molecular Life Sciences, Vol. 81, No. 4, 2024, pp. 456-475.
[16] A. J. Morwood, I. A. El-Karim, S. A. Clarke, F. T. Lundy, The Role of Extracellular Matrix (ECM) Adhesion Motifs in Functionalised Hydrogels, Molecules, Vol. 28, No. 12, 2023, pp. 4616.
[17] I. H. Lokman, et al., Characterization of Keratin from Duck Feather Waste: Structural and Compositional Analysis, International Journal of Biological Macromolecules, Vol. 152, 2020, pp. 1-10.
[18] O.A. Meko, S.O. Eraga, M.I. Arhewoh, Effect of extraction parameters on some properties of keratin obtained from waste chicken feathers. Tropical Journal of Natural Product Research, Vol. 8, No. 6, 2024, pp. 7423-7430.
[19] S.D. Marliyana, T.I.S.T. Dewi, T. Kusumaningsih, Extraction of ?-keratin from poultry feather waste using sodium metabisulfite and sodium dodecyl sulfate, Malaysian Journal of Analytical Sciences, Vol. 28, No. 1, 2024, pp. 116-126.
[20] S. Banasaz, V. Ferraro, Keratin from animal by-products: structure, characterization, extraction and application—A review, Polymers, Vol. 16, No. 14, 1999, pp. 1999.
[21] M Skerget, M Colnik, L.F. Zemljic, L. Gradisnik, T.Z. Semren, B.T. Lovakovic, U. Maver, Efficient and green isolation of keratin from poultry feathers by subcritical water, Polymers, Vol. 15, No. 12, 2023, pp. 2658.
[22] S.G. Giteru, D.H. Ramsey, Y. Hou, L. Cong, A. Mohan, A/E-D.A. Bekhit, Wool keratin as a novel alternative protein: A comprehensive review of extraction, purification, nutrition, safety, and food applications, Comprehensive Reviews in Food Science and Food Safety, Vol. 22, No. 1, 2022, pp. 643-87.
[23] Y.S. Khoo, T.C. Tjong, J.W. Chew, X. Hu, Techniques for recovery and recycling of ionic liquids: A review, Science of the Total Environment, Vol. 922, 2024, pp. 171238.
[24] R. Salas, R. Villa, F. Velasco, F.G. Cirujano, S. Nieto, N. Martin, E. Garcia-Verdugo, J. Dupont, P. Lozano, Ionic liquids in polymer technology, Green Chemistry, 2025.
[25] Y. Zhuo, H-L. Cheng, Y-G. Zhao, H-R. Cui, Ionic liquids in pharmaceutical and biomedical applications: A review, Pharmaceutics, Vol. 16, No. 1, 2024, pp. 151.
[26] X. Lin, K. Jiang, X. Liu, D. Han, Review on development of ionic liquids in lignocellulosic biomass refining, Journal of Molecular Liquids, Vol. 359, No. 24, 2022, pp. 119326.
[27] F. Yang, C. Chen, D. Ni, Y. Yang, J. Tian, Y. Li, S. Chen, X. Ye, L. Wang, Effects of fermentation on bioactivity and the composition of polyphenols contained in polyphenol-rich foods: A review, Foods, Vol. 12, No. 17, 2023, pp. 3315.
[28] N. Nayak, R.R. Bhujle, N.A. Nanje-Gowda, S. Chakraborty, K. Siliveru, J. Subbiah, C. Brennan, Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review, Heliyon, Vol. 10, pp. e30921.
[29] M. Kammoun, A. Margellou, V.B. Toteva, A. Aladjadjiyan, A.F. Sousa, S.V. Luis, E. Garcia-Verdugo, K.S. Trantafyllidis, A. Richel, The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds, RSC Advances, Vol. 13, 2023, pp. 21587-21612.
[30] R.S. Abolore, S. Jaiswal, A.K. Jaiswal, Green and sustainable pretreatment methods for cellulose extraction from lignocellulosic biomass and its applications: A review, Carbohydrate Polymer Technologies and Applications, Vol. 7, 2024, pp. 100396.
[31] D. Kim, S-G. Kang, Y.K. Chang, M. Kwak, Two-step macromolecule separation process with acid pretreatment and high-shear-assisted extraction for microalgae-based biorefinery, Sustainability, Vol. 16, No. 17, 2024, pp. 7589.
[32] P. Bharmoria, A.A. Tietze, D. Mondal, T.S. Kang, A. Kumar, M.G. Freire, Do ionic liquids exhibit the required characteristics to dissolve, extract, stabilize, and purify proteins? Past-present-future assessment, Chemical Reviews, Vol. 124, No. 6, 2024, pp. 3037-3084.
[33] S.K. Panja, S. Kumar, B. Haddad, A.R. Patel, D. Villemin, H-M Amine, S. Bera, M. Debdab. role of multiple intermolecular H-bonding interactions in molecular cluster of hydroxyl-functionalized imidazolium ionic liquid: an experimental, topological, and molecular dynamics study. Physical Chemistry Research, Vol. 4, No. 4, 2024, pp. 369-388.
[34] C. Polesca, A Al Gatta, H. Passos, J.A.P. Coutinho, J.P. Hallett, M.G. Freire, Sustainable keratin recovery process using a bio-based ionic liquid aqueous solution and its techno-economic assessment, Green Chemistry, Vol. 25, 2023, pp. 3995-4003.
[35] A. Cordova, S. Catalan, V. Carrasco, F.O. Farias, J. Trentin, J. Lopez, F. Salazar, C.U. Mussagy, Sustainable assessment of ultrasound-assisted extraction of anthocyanins with bio-based solvents for upgrading grape pomace Cabernet Sauvignon derived from a winemaking process, Ultrasonics Sonochemistry, Vol. 112, 2025, pp. 107201.
[36] S. Kong, Y. Liu, R. Tang, Q. Liao, D. Bai, D. Lv, Z. Xu, L. Lin, H. Li, Ultrasound-assisted extraction of prenylated flavonoids from Sophora flavescens: Optimization, mechanistic characterization, antioxidant and anti-inflammatory activities, Industrial Crops and Product, Vol. 225, 2025, pp. 120559.
[37] F. Pourjavaheri, S. O. Pour, O. A. H. Jones, P. M. Smooker, R. Brklja?a, F. Sherkat, E. W. Blanch, A. Gupta, R. A. Shanks, Extraction of keratin from waste chicken feathers using sodium sulfide and l-cysteine, Process Biochemistry, Vol. 82, 2019, pp. 205-214.
[38] G. Marques, Optimization of Phenolic Compounds Extraction and Antioxidant Activity from Inonotus hispidus Using Ultrasound-Assisted ExtractionTechnology, Metabolites, Vol. 13, No. 4, 2023, pp. 524.
[39] D. Rosarina, R. N. Dimas, N. S. R. Chandra, E. F. Sari, H. Hermansyah, Optimization of Ultrasonic-Assisted Extraction (UAE) Method Using Natural Deep Eutectic Solvent (NADES) to Increase Curcuminoid Yield from Curcuma longa L., Curcuma xanthorrhiza, and Curcuma mangga Val., Molecules, Vol. 27, No. 18, 2022, pp. 6080.
[40] J. Sun, G. M. Santiago, F. Yan, W. Zhou, P. Rudolf, G. Portale, M. Kamperman, Bioinspired Processing of Keratin into Upcycled Fibers through pH-Induced Coacervation, ACS Sustainable Chemistry & Engineering, Vol. 11, No. 5, 2023, pp. 1985-1994.
[41] A. Mengistu, G. Andualem, M. Abewaa, D. Birhane, Keratin extraction optimization from poultry feather using response surface- Box-Behnken experimental design method, Results in Engineering, Vol. 22, 2024, pp. 102360.
[42] S. Perez-Vila, M. Fenelon, D. Hennessy, J.A. O’Mahony, L.G. Gomez-Mascaraque, Impact of the extraction method on the composition and solubility of leaf protein concentrates from perennial ryegrass (Lolium perenne L.), Food Hydrocolloids, Vol. 147(A), 2024, pp. 109372.
[43] K. Oussadi, S. Al-Farraj, B. Benabdallah, A. Benettayeb, B. Haddou, M. Sillanpaa, Wool keratin as novel, alternative, low-cost adsorbent rich in various -N and -S proteins for eliminating methylene blue from water, Biomass Conversion and Biorefinery, Vol. 15, 2025, pp. 4803-4817.
[44] R. A. Pérez, B. Albero, Ultrasound-assisted extraction methods for the determination of organic contaminants in solid and liquid samples, Trends in Analytical Chemistry, Vol. 166, 2023.
[45] A. B. D. Nandiyanto, R. Oktiani, R. Ragadhita, How to Read and Interpret FTIR Spectroscope of Organic Material, Indonesian Journal of Science and Technology, Vol. 4, No. 1, 2019, pp. 97.
[46] M. Škerget, et al., Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical Water, Polymers, Vol. 15, No. 12, 2023, pp. 2658-2658.
[47] S. Alvarez, Development of innovative bio-based films with keratin extracted from duck feathers, English: Universite de Pau et des Pays de l’Adour, 2024.
[48] W. Kanoksilapatham, W. Intagun, A Review: Biodegradation and Applications of Keratin Degrading Microorganisms and Keratinolytic Enzymes, Focusing on Thermophiles and Thermostable Serine Proteases, American Journal of Applied Sciences, Vol. 14, No. 11, 2017, pp. 1016-1023.
[49] Y. Su, et al., Crystalline structures of l-cysteine and l-cystine: a combined theoretical and experimental characterization, Amino Acids, Vol. 54, No. 8, 2022, pp. 1123-1133.
[50] C. L. Feider, A. Krieger, R. J. DeHoog, L. S. Eberlin, Ambient ionization mass spectrometry: recent developments and applications, Analytical Chemistry, Vol. 91, No. 7, 2019, pp. 4266-4290.
[51] I. A. Ismail, R. Riga, O. Suryani, M. Insani, N. L. Pernadi, A. Febriyanti, Analisis Spektrum 1H-NMR: Penjelasan Sederhana, International Journal of Academic Multidisciplinary Research (IJAMR), Vol. 6, No. 12, pp. 336-342.
[2] E. C. Rodriguez-Merchan, Pathophysiology of Bone Trauma: Comprehensive Contemporary Insights, Injury, Vol. 55, No. 1, 2024, pp. 12-25.
[3] E. M. Curtis, et al., Worldwide Bone Damage Epidemiology: Trends, Projections, and Risk Factors, The Lancet Rheumatology, Vol. 6, No. 1, 2024, pp. e45-e60.
[4] J. A. Kanis, et al., Global Trends in Bone Damage Prevalence and Projections: A Comprehensive Analysis, Osteoporosis International, Vol. 35, No. 2, 2024, pp. 267-285.
[5] X. Wang, et al., Advanced 3D Nanofiber Scaffolds in Tissue Engineering: Biomaterial Innovations, Advanced Materials, Vol. 36, No. 12, 2024, pp. 2311456.
[6] H. Chen, et al., Porous 3D Nanofiber Scaffolds: Emerging Strategies in Regenerative Medicine, Nature Biomedical Engineering, Vol. 8, No. 2, 2024, pp. 145-162.
[7] L. Zhang, et al., Advanced 3D Matrix Design for Bone Cell Proliferation and Differentiation, Tissue Engineering Part A, Vol. 30, No. 5-6, 2024, pp. 267-285.
[8] Y. Zhang, et al., Advanced Biomaterials for Tissue Regeneration: Current Progress and Challenges, Advanced Science, Vol. 8, No. 23, 2021, pp. 2101167.
[9] X. Liu, A. L. Miller, J. P. Urban, Engineered Scaffolds for Regenerative Medicine: Advances and Challenges, Nature Reviews Materials, Vol. 8, No. 4, 2023, pp. 215-230.
[10] M. Rodriguez-Garcia, et al., Synergistic Approaches in Combining Natural and Synthetic Biopolymers for Bone Regeneration, Acta Biomaterialia, Vol. 168, 2024, pp. 45-62.
[11] P. Zhao, et al., Non-Toxic Synthetic Biopolymers for Advanced Bone Tissue Engineering, Biomaterials Science, Vol. 11, No. 18, 2023, pp. 6145-6167.
[12] L. Zhang, et al., Comprehensive Analysis of Poly(3-hydroxybutyrate) Properties in Advanced Biomaterial Applications, Biomacromolecules, Vol. 24, No. 7, 2023, pp. 3456-3472.
[13] H. Chen, et al., Keratin-Based Scaffolds for Enhanced Bone Tissue Integration, Acta Biomaterialia, Vol. 165, 2023, pp. 78-95.
[14] X. Liu, et al., Comprehensive Analysis of Keratin Protein Structure and Molecular Characteristics, International Journal of Molecular Sciences, Vol. 25, No. 3, 2024, pp. 1456.
[15] J. Rodriguez-Martinez, et al., Cell Adhesion Motifs in Extracellular Matrix Proteins, Cellular and Molecular Life Sciences, Vol. 81, No. 4, 2024, pp. 456-475.
[16] A. J. Morwood, I. A. El-Karim, S. A. Clarke, F. T. Lundy, The Role of Extracellular Matrix (ECM) Adhesion Motifs in Functionalised Hydrogels, Molecules, Vol. 28, No. 12, 2023, pp. 4616.
[17] I. H. Lokman, et al., Characterization of Keratin from Duck Feather Waste: Structural and Compositional Analysis, International Journal of Biological Macromolecules, Vol. 152, 2020, pp. 1-10.
[18] O.A. Meko, S.O. Eraga, M.I. Arhewoh, Effect of extraction parameters on some properties of keratin obtained from waste chicken feathers. Tropical Journal of Natural Product Research, Vol. 8, No. 6, 2024, pp. 7423-7430.
[19] S.D. Marliyana, T.I.S.T. Dewi, T. Kusumaningsih, Extraction of ?-keratin from poultry feather waste using sodium metabisulfite and sodium dodecyl sulfate, Malaysian Journal of Analytical Sciences, Vol. 28, No. 1, 2024, pp. 116-126.
[20] S. Banasaz, V. Ferraro, Keratin from animal by-products: structure, characterization, extraction and application—A review, Polymers, Vol. 16, No. 14, 1999, pp. 1999.
[21] M Skerget, M Colnik, L.F. Zemljic, L. Gradisnik, T.Z. Semren, B.T. Lovakovic, U. Maver, Efficient and green isolation of keratin from poultry feathers by subcritical water, Polymers, Vol. 15, No. 12, 2023, pp. 2658.
[22] S.G. Giteru, D.H. Ramsey, Y. Hou, L. Cong, A. Mohan, A/E-D.A. Bekhit, Wool keratin as a novel alternative protein: A comprehensive review of extraction, purification, nutrition, safety, and food applications, Comprehensive Reviews in Food Science and Food Safety, Vol. 22, No. 1, 2022, pp. 643-87.
[23] Y.S. Khoo, T.C. Tjong, J.W. Chew, X. Hu, Techniques for recovery and recycling of ionic liquids: A review, Science of the Total Environment, Vol. 922, 2024, pp. 171238.
[24] R. Salas, R. Villa, F. Velasco, F.G. Cirujano, S. Nieto, N. Martin, E. Garcia-Verdugo, J. Dupont, P. Lozano, Ionic liquids in polymer technology, Green Chemistry, 2025.
[25] Y. Zhuo, H-L. Cheng, Y-G. Zhao, H-R. Cui, Ionic liquids in pharmaceutical and biomedical applications: A review, Pharmaceutics, Vol. 16, No. 1, 2024, pp. 151.
[26] X. Lin, K. Jiang, X. Liu, D. Han, Review on development of ionic liquids in lignocellulosic biomass refining, Journal of Molecular Liquids, Vol. 359, No. 24, 2022, pp. 119326.
[27] F. Yang, C. Chen, D. Ni, Y. Yang, J. Tian, Y. Li, S. Chen, X. Ye, L. Wang, Effects of fermentation on bioactivity and the composition of polyphenols contained in polyphenol-rich foods: A review, Foods, Vol. 12, No. 17, 2023, pp. 3315.
[28] N. Nayak, R.R. Bhujle, N.A. Nanje-Gowda, S. Chakraborty, K. Siliveru, J. Subbiah, C. Brennan, Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review, Heliyon, Vol. 10, pp. e30921.
[29] M. Kammoun, A. Margellou, V.B. Toteva, A. Aladjadjiyan, A.F. Sousa, S.V. Luis, E. Garcia-Verdugo, K.S. Trantafyllidis, A. Richel, The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds, RSC Advances, Vol. 13, 2023, pp. 21587-21612.
[30] R.S. Abolore, S. Jaiswal, A.K. Jaiswal, Green and sustainable pretreatment methods for cellulose extraction from lignocellulosic biomass and its applications: A review, Carbohydrate Polymer Technologies and Applications, Vol. 7, 2024, pp. 100396.
[31] D. Kim, S-G. Kang, Y.K. Chang, M. Kwak, Two-step macromolecule separation process with acid pretreatment and high-shear-assisted extraction for microalgae-based biorefinery, Sustainability, Vol. 16, No. 17, 2024, pp. 7589.
[32] P. Bharmoria, A.A. Tietze, D. Mondal, T.S. Kang, A. Kumar, M.G. Freire, Do ionic liquids exhibit the required characteristics to dissolve, extract, stabilize, and purify proteins? Past-present-future assessment, Chemical Reviews, Vol. 124, No. 6, 2024, pp. 3037-3084.
[33] S.K. Panja, S. Kumar, B. Haddad, A.R. Patel, D. Villemin, H-M Amine, S. Bera, M. Debdab. role of multiple intermolecular H-bonding interactions in molecular cluster of hydroxyl-functionalized imidazolium ionic liquid: an experimental, topological, and molecular dynamics study. Physical Chemistry Research, Vol. 4, No. 4, 2024, pp. 369-388.
[34] C. Polesca, A Al Gatta, H. Passos, J.A.P. Coutinho, J.P. Hallett, M.G. Freire, Sustainable keratin recovery process using a bio-based ionic liquid aqueous solution and its techno-economic assessment, Green Chemistry, Vol. 25, 2023, pp. 3995-4003.
[35] A. Cordova, S. Catalan, V. Carrasco, F.O. Farias, J. Trentin, J. Lopez, F. Salazar, C.U. Mussagy, Sustainable assessment of ultrasound-assisted extraction of anthocyanins with bio-based solvents for upgrading grape pomace Cabernet Sauvignon derived from a winemaking process, Ultrasonics Sonochemistry, Vol. 112, 2025, pp. 107201.
[36] S. Kong, Y. Liu, R. Tang, Q. Liao, D. Bai, D. Lv, Z. Xu, L. Lin, H. Li, Ultrasound-assisted extraction of prenylated flavonoids from Sophora flavescens: Optimization, mechanistic characterization, antioxidant and anti-inflammatory activities, Industrial Crops and Product, Vol. 225, 2025, pp. 120559.
[37] F. Pourjavaheri, S. O. Pour, O. A. H. Jones, P. M. Smooker, R. Brklja?a, F. Sherkat, E. W. Blanch, A. Gupta, R. A. Shanks, Extraction of keratin from waste chicken feathers using sodium sulfide and l-cysteine, Process Biochemistry, Vol. 82, 2019, pp. 205-214.
[38] G. Marques, Optimization of Phenolic Compounds Extraction and Antioxidant Activity from Inonotus hispidus Using Ultrasound-Assisted ExtractionTechnology, Metabolites, Vol. 13, No. 4, 2023, pp. 524.
[39] D. Rosarina, R. N. Dimas, N. S. R. Chandra, E. F. Sari, H. Hermansyah, Optimization of Ultrasonic-Assisted Extraction (UAE) Method Using Natural Deep Eutectic Solvent (NADES) to Increase Curcuminoid Yield from Curcuma longa L., Curcuma xanthorrhiza, and Curcuma mangga Val., Molecules, Vol. 27, No. 18, 2022, pp. 6080.
[40] J. Sun, G. M. Santiago, F. Yan, W. Zhou, P. Rudolf, G. Portale, M. Kamperman, Bioinspired Processing of Keratin into Upcycled Fibers through pH-Induced Coacervation, ACS Sustainable Chemistry & Engineering, Vol. 11, No. 5, 2023, pp. 1985-1994.
[41] A. Mengistu, G. Andualem, M. Abewaa, D. Birhane, Keratin extraction optimization from poultry feather using response surface- Box-Behnken experimental design method, Results in Engineering, Vol. 22, 2024, pp. 102360.
[42] S. Perez-Vila, M. Fenelon, D. Hennessy, J.A. O’Mahony, L.G. Gomez-Mascaraque, Impact of the extraction method on the composition and solubility of leaf protein concentrates from perennial ryegrass (Lolium perenne L.), Food Hydrocolloids, Vol. 147(A), 2024, pp. 109372.
[43] K. Oussadi, S. Al-Farraj, B. Benabdallah, A. Benettayeb, B. Haddou, M. Sillanpaa, Wool keratin as novel, alternative, low-cost adsorbent rich in various -N and -S proteins for eliminating methylene blue from water, Biomass Conversion and Biorefinery, Vol. 15, 2025, pp. 4803-4817.
[44] R. A. Pérez, B. Albero, Ultrasound-assisted extraction methods for the determination of organic contaminants in solid and liquid samples, Trends in Analytical Chemistry, Vol. 166, 2023.
[45] A. B. D. Nandiyanto, R. Oktiani, R. Ragadhita, How to Read and Interpret FTIR Spectroscope of Organic Material, Indonesian Journal of Science and Technology, Vol. 4, No. 1, 2019, pp. 97.
[46] M. Škerget, et al., Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical Water, Polymers, Vol. 15, No. 12, 2023, pp. 2658-2658.
[47] S. Alvarez, Development of innovative bio-based films with keratin extracted from duck feathers, English: Universite de Pau et des Pays de l’Adour, 2024.
[48] W. Kanoksilapatham, W. Intagun, A Review: Biodegradation and Applications of Keratin Degrading Microorganisms and Keratinolytic Enzymes, Focusing on Thermophiles and Thermostable Serine Proteases, American Journal of Applied Sciences, Vol. 14, No. 11, 2017, pp. 1016-1023.
[49] Y. Su, et al., Crystalline structures of l-cysteine and l-cystine: a combined theoretical and experimental characterization, Amino Acids, Vol. 54, No. 8, 2022, pp. 1123-1133.
[50] C. L. Feider, A. Krieger, R. J. DeHoog, L. S. Eberlin, Ambient ionization mass spectrometry: recent developments and applications, Analytical Chemistry, Vol. 91, No. 7, 2019, pp. 4266-4290.
[51] I. A. Ismail, R. Riga, O. Suryani, M. Insani, N. L. Pernadi, A. Febriyanti, Analisis Spektrum 1H-NMR: Penjelasan Sederhana, International Journal of Academic Multidisciplinary Research (IJAMR), Vol. 6, No. 12, pp. 336-342.