The leather industry generates a significant amount of various wastes, and their utilisation is a serious task for researchers. Ways to reuse or decontaminate such waste are being developed intensively. Unfortunately, the reuse of finished leather, which eventually becomes waste, is almost unexplored. The present research is designed to evaluate the potential of finished leather hydrolysis to obtain protein hydrolysates suitable for reuse in leather processing and to establish factors that influence leather quality during such an application. Enzyme preparation Vilzim PRO Conc was characterised as a potential agent for such hydrolysis. The addition of 3–4% Vilzim PRO Conc is appropriate for the enzymatic stage of the hydrolysis process. It was established that after alkaline-enzymatic hydrolysis of used leather powder the obtained hydrolysates are complicated systems containing proteins, chromium compounds, dyes, fatliquoring materials, etc. Hydrolysates could be used for the dyeing of chromed leather. The method of preparation for dyeing and dyeing of wet-blue leather with the use of hydrolysate influences the depth of dye penetration and the quality of finished leather. It was established that the neutralisation process is not necessary before such dyeing. Also, an increased amount of formic acid is necessary to improve the bonding of fatliquors with dermal tissue after treatment with hydrolysate.
1. Scopel, B., Lamers, D. L., Matos, E., Baldasso C. and Dettmer, A. Collagen hydrolysate extraction from chromed leather waste for polymeric film production. J. Am. Leather Chem. Assoc., 2016, 111(1), 30–40.
2. Parisi, M., Nanni, A. and Colonna, M. Recycling of chrome-tanned leather and its utilization as polymeric materials and in polymer-based composites: a review. Polymers, 2021, 13(3), 429.
https://doi.org/10.3390/polym13030429
3. Zainescu, G., Albu L., Deselnicu, D., Constantinescu, R. R., Vasilescu, A. M., Nichita, P. et al. A new concept of complex valorization of leather wastes. Mater. Plast., 2014, 51(1), 90–93.
4. Ozgunay, H., Colak, S. M., Mutlu, M. M. and Akyüz, F. Characterization of leather industry wastes, Pol. J. Environ. Stud., 2007, 16(6), 867–873.
5. Masilamani, D., Madhan, B., Shanmugam, G., Palanivel, S. and Narayan, B. Extraction of collagen from raw trimming wastes of tannery: a waste to wealth approach. J. Clean. Prod., 2016, 113, 338–344.
https://doi.org/10.1016/j.jclepro.2015.11.087
6. Thazeem, B., Umesh, M., Mani, V. M., Beryl, G. P. and Preethi, K. Biotransformation of bovine tannery fleshing into utilizable product with multifunctionalities. Biocatal. Biotransformation, 2021, 39(2), 81–99.
https://doi.org/10.1080/10242422.2020.1786071
7. Chojnacka, K., Skrzypczak, D., Mikula, K., Witek-Krowiak, A., Izydorczyk, G., Kuligowski, K. et al. Progress in sustainable technologies of leather wastes valorization as solutions for the circular economy. J. Clean. Prod., 2021, 313, 127902.
https://doi.org/10.1016/j.jclepro.2021.127902
8. Sasia, A. A., Sang, P. and Onyuka, A. Recovery of collagen hydrolysate from chrome leather shaving tannery waste through two-step hydrolysis using magnesium oxide and bating enzyme. J. Soc. Leather Technol. Chem., 2019, 103(2), 80–84.
9. Stefan, D. S., Pantazi, M. and Meghea, I. Opportunities for capitalization of leather and footwear waste by composting. In Proceedings of the 12th International Multidisciplinary Scientific GeoConference of Modern Management of Mine Producing, Geology and Environmental Protection (SGEM), Albena, Bulgaria, 17–23 June 2012. SGEM, 2012, 587–596.
10. Jadhav, N. C. and Jadhav, A. C. Waste and 3r’s in footwear and leather sectors. In Leather and Footwear Sustainability. Textile Science and Clothing Technology (Muthu, S. S., ed.). Springer, Singapore, 2020, 261–293.
https://doi.org/10.1007/978-981-15-6296-9_10
11. Przepiórkowska, A., Chrońska, K. and Zaborski, M. Chrome-tanned leather shavings as a filler of butadiene–acrylonitrile rubber. J. Hazard. Mater., 141(1), 2007, 252–257.
https://doi.org/10.1016/j.jhazmat.2006.06.136
12. Senthil, R., Hemalatha, T., Manikandan, R., Das, B. N. and Sastry, T. P. Leather boards from buffing dust: a novel perspective. Clean Technol. Environ. Policy, 2015, 17, 571–576.
https://doi.org/10.1007/s10098-014-0831-7
13. Senthil, R., Inbasekaran, S., Gobi, N., Das, B. N. and Sastry, T. P. Utilisation of finished leather wastes for the production of blended fabrics. Clean Technol. Environ. Policy, 2015, 17, 1535–1546.
https://doi.org/10.1007/s10098-014-0881-x
14. Aguirre-Cruz, G., León-López, A., Cruz-Gómez, V., Jiménez-Alvarado, R. and Aguirre-Álvarez, G. Collagen hydrolysates for skin protection: oral administration and topical formulation. Antioxidants, 2020, 9(2), 181.
https://doi.org/10.3390/antiox9020181
15. Wang, H. A review of the effects of collagen treatment in clinical studies. Polymers, 2021, 13(22), 3868.
https://doi.org/10.3390/polym13223868
16. León-López, A., Morales-Peñaloza, A., Martínez-Juárez, V. M., Vargas-Torres, A., Zeugolis, D. I. and Aguirre-Álvarez, G. Hydrolyzed collagen – sources and applications. Molecules, 2019, 24, 4031.
https://doi.org/10.3390/molecules24224031
17. Zhao, L., Mu, S., Wang, W. and Gu, H. Toxicity evaluation of collagen hydrolysates from chrome shavings and their potential use in the preparation of amino acid fertilizer for crop growth. J. Leather Sci. Eng., 2022, 4, 2.
https://doi.org/10.1186/s42825-021-00072-1
18. Ding, X., Li, Y., Chen, J., Huang, X., Chen, L. and Hu, Z. Sustainable utilization of finished leather wastes: a novel collagen hydrolysate-based gypsum additive with high-retarding performance. Process Saf. Environ. Prot., 2023, 172, 451–461.
https://doi.org/10.1016/j.psep.2023.02.040
19. Voinitchi, C., Gaidau, C., Tudorie, F. C., Niculescu, M., Stanca, M. and Alexe, C. A. Collagen and keratin hydrolysates to delay the setting of gypsum plaster. Materials, 2022, 15(24), 8817.
https://doi.org/10.3390/ma15248817
20. Pati, A. and Chaudhary, R. Studies on the generation of biogas from collagen hydrolysate obtained from chrome shavings by alkaline hydrolysis: a greener disposal method. Res. J. Recent Sci., 2013, 2, 234–240.
21. Cantera, C. S., Greco, C. A., De Giusti, M. and Bereciartua, P. Dechroming of shavings. Part 1: enzymic alkaline treatment. Study of variables. Das Leder, 1994, 11, 265–270.
22. Rao, J. R., Thanikaivelan, P., Sreeram, K. J. and Nair, B. U. Green Route for the utilization of chrome shavings (chromium-containing solid waste) in tanning industry. Environ. Sci. Technol. 2002, 36(6), 1372–1376.
https://doi.org/10.1021/es015635s
23. Zaides, A., Mikhailov, A. and Pushenko, O. Модифицированный метод определения оксипролина (Modified method for hydroxyproline determination). Биохимия, 1964, 29, 5–7.
24. Golovteeva, A. A., Kutsidi, D. A. and Sankin, L. B. Лабораторный практикум по химии и технологии кожи и меха (Laboratory Practicum on Chemistry and Technology of Leather and Fur). Легкая и пищевая пром., Moscow, 1982.
25. ISO 5398-2:2009. Leather – Chemical determination of chromic oxide content – Part 2: quantification by colorimetric determination.
26. ISO 4048:2008. Leather – Chemical tests – Determination of matter soluble in dichloromethane and free fatty acid content.
27. ISO 3376:2011. Leather physical and mechanical tests – Determination of tensile strength and percentage extension.
28. Kubilius, K., Valeikiene, V. and Valeika, V. Collagen hydrolysate from chromed shavings for leather finish. In Proceedings of the 8th International Conference on Advanced Material and Systems (ICAMS), Bucharest, Romania, 1–3 October 2020. ICAMS, 2020, 399–402.
https://doi.org/10.24264/icams-2020.IV.10
