A Novel Approach to Enzymatic Unhairing and Fiber Opening of Skin Using Enzymes Immobilized on Magnetite Nanoparticles

One of the prerequisites for making leather is to remove the inter-fibrillar proteins and noncollagenous materials, such as hair, flesh, etc. These proteinous and nonproteinous materials are removed in several steps, cumulatively known as the pretanning (or beam house) operations. A paradigm shift from chemical- to enzyme-based processes ensured that these noncollagenous materials were removed using enzymatic digestion rather than brutal osmotic forces employing chemicals like lime and sulfide. In order to make sure that a cocktail of enzymes (protease + amylase) have broad application and stability, their immobilization onto matrices that can enable overcoming such drawbacks is essential. This work, taking clues from the catalytic applications of nanoparticle-immobilized enzymes looks at metal oxide nanoparticle-immobilized enzymes for unhairing and fiber opening applications in a facile manner. Iron oxide (Fe₃O₄) nanoparticles have been selected for the present study since metal oxides are proven as an unbeaten matrix for protein tagging. In the present study, a cocktail of protease and amylase (fibrozyme) was used as control, and a nanoparticle-immobilized enzyme cocktail (nanozyme) was used as the experimental sample. Enzyme concentration was fixed as 3% of raw skin weight, while drumming in a stainless steel vessel was looked at as the application method. Nanozyme-treated leather samples were analyzed for their unhairing and fiber opening efficiency. Histological studies, physical strength, and organoleptic studies of control and experimental sample leathers were also carried out. Microstructural analysis based on histopatholgy studies of fibrozyme- and nanozyme-treated tissues exhibited no significant change in tissue morphology, which confirms that nanoparticles did not have any adverse effect on the skin. Scanning electron microscopy (SEM) images of fibrozyme- and nanozyme-treated leathers show the degree of fiber opening, and an energy dispersive X-ray spectrum (EDS) shows the elements present on the skin matrix. This study provides a newer insight for a cleaner, economical, and sustainable method of leather processing.