Every year, the tanning industry recovers around 8 million tons of raw hides from the food industry. According to a UNIDO study, this prevents the emission of 5 million tons of greenhouse gases that would otherwise result from disposing of these scraps as waste. Despite its circular nature, leather processing still has an environmental impact, mainly due to the intensive use of water and chemicals. To tackle these challenges, the tanning industry is undergoing a scientific revolution: thanks to biotechnologies and nanotechnologies, production processes are being rethought by replacing polluting components and introducing new functionalities.
ENZYMES AND MICROORGANISMS: BIOTECHNOLOGY LIGHTENS THE ENVIRONMENTAL LOAD
“Applied biotechnology in tanning – explains Elisabetta Scaglia, Head of Sustainability at UNIC – has two main fields of action: on one hand, enzymes are used directly in tanning processes, and on the other, bio-based chemicals are produced, derived from plant or biological sources as alternatives to petrochemical-based ones.” Enzymes, highly selective biological catalysts, are applied in several stages of processing, particularly the most environmentally critical ones. During soaking, for instance, they act on elastin fibers, eliminating impurities, pigments, and residual tissues, loosening the fibrous structure of the hide. In the liming phase, sodium sulfide can be replaced with more delicate and effective proteolytic enzymes. Bacteria also play a crucial role: they are the basis of modern purification systems, feeding on organic substances found in wastewater. “By analyzing the microorganism populations in treatment plants – continues Scaglia – we can even diagnose the efficiency of the plant. Work can also be done on air pollution: some biofilters, for example, are made with mussel shells, food waste with excellent absorbent properties thanks to the porous structure of calcium carbonate.” Challenges remain: “With enzymes and bacteria, very precise control is required – Scaglia points out – because they are living organisms. Dosage, pH, temperature: everything must be finely tuned.” But the benefits are significant, also in terms of climate: “Bio-based chemicals, being derived from plant materials that have already absorbed CO₂ during growth, do not add new carbon dioxide to the atmosphere, unlike fossil-based products.”
FUNCTIONAL LEATHER, INTERACTIVE LEATHER: THE INFINITE POSSIBILITIES OF NANOTECHNOLOGY
If biotechnology helps us do better what we already know, nanotechnology allows us to achieve the impossible. Leather can become waterproof, antibacterial, self-extinguishing, conductive. “With nanoparticles – explains Paolo Netti, Professor of Industrial Bioengineering at the University Federico II of Naples – we can deliver tanning agents with molecular precision, avoiding excesses and reducing waste discharges.” The benefit is not only environmental: “With nano-tanning – Netti continues – we reduce process times from days to just minutes, and in some cases we could eliminate the use of water altogether, one of the major critical issues of traditional tanning.” The great promise of nanotechnology is the advanced functionalization of leather. We can use silver nanoparticles to make it antibacterial, silica particles to increase abrasion and cut resistance, and graphene to enhance conductivity and strength. “We can treat different portions of the leather differently, creating micro-zones with specific properties: a conductive zone, a water-repellent one, a self-extinguishing one,” Netti emphasizes.
The result? Smart leathers that interact with the environment or even with the user. “We can apply conductive inks to leather – Netti concludes – turning it into a living interface: a jacket that measures vital signs, an item that recharges phones, or a leather interior for sports cars that functions as a touch screen.” The future of leather thus lies in labs and research centers, where bio and nanotech work together to reduce environmental impact and boost performance. The outcome? Smarter and more sustainable materials, ready to dress not only the body but also a new way of producing, consuming, and innovating.
