Leather industry: a new chair to promote revolutionary and virtuous tanning
The University of Montpellier has inaugurated the SICLE.e industrial chair, focusing on an innovative silicon-based leather tanning process. It is one of the first projects in Occitanie to receive funding under the call for projects for industrial chairs from the(ANR) (ANR). Spotted during a webinar to raise awareness of "Joint Laboratories" organized as part of Montpellier's University Innovation Cluster ( PUI), the project was then supported by the university's Innovation and Partnerships Department (DIPA).
Although he was the one who brought the project to the ANR, Gilles Subra insists that this new chair is the result of an eminently "collective" effort. Inaugurated on Tuesday, May 20, at the University of Montpellier in the presence of President Philippe Augé, the SICLE.e chair brings together multiple partners: the CTC group,the Max Mousseron Biomolecules Institute ( IBMM),the Charles Gerhardt Institute of Montpellier (ICGM), and CIRAD's BioWooEB laboratory. Their goal is to promote a more virtuous leather industry by developing new technologies based on the use of silicon.
The story begins in 2021. At that time, behind closed doors in their laboratories, Ahmad Mehdi's team at ICGM and Gilles Subra's team at IBMM had already been working for several years on combining silicon and collagen "in the context of health and regenerative medicine issues, "says Gilles Subra, a researcher at IBMM. So when a doctoral student in his team learned that the Centre Technique du Cuir (CTC) group was looking for partners to find innovative tanning solutions, he and his colleagues stepped up to the plate. "Collagen is the main component of leather, so we quickly realized that the techniques we were using for regenerative medicine could be used to tan hides,"he explains.
Game changer
In the wake of this, the researchers and the CTC group agreed on three research contracts to kick off the collaboration, followed by two patents in 2024, before jointly submitting this industrial chair project to the ANR that same year. "There were so many opportunities for development that it was impossible to continue with ad hoc contracts. We needed to give ourselves more time to explore new technologies and give the projects a chance to succeed; the chair was the perfect solution." In short, a lasting cooperation and very promising avenues of research. "The ANR's requirements stipulated that the innovation had to be disruptive, a 'game changer', and of interest to an entire economic sector, not just one company. A chair has an impact on an entire value chain," explains Gilles Subra. After ticking all these boxes, in June 2024, the team was the very first winner of the ANR's Industrial Chairs call for projects in the Occitanie region.
In concrete terms, it is in the process of developing a genuine alternative to chrome tanning, which until now has produced the highest quality results despite its potential impact on the environment. Unlike the metals used in most cases, silicon is an inexhaustible and non-toxic resource. "The key to our innovation is that silicic acid is able to polymerize when it enters the skin, creating networks between collagen chains. This is what transforms the skin into leather, giving it rot-proof qualities, "explains Gilles Subra.
Two patents
Unlike traditional tanning methods, which produce a bluish-colored hide, silicon tanning produces white leather. "This makes it possible to create pastel shades that were previously unattainable." Another significant advantage is that this process does not produce any toxic waste. Finally, the silica chains that set the tanning process are capable of forming lasting bonds with molecules with various properties, and of "functionalizing" the leather in a sustainable way. In short, it is possible to create antifungal leather using a molecule that can spread throughout the silica network, as well as water-repellent, fluorescent, or even "anti-counterfeit" leather by inserting an invisible marking that can be revealed when exposed to certain lights. This revolutionary aspect was the subject of the team's second patent, following the first patent on the tanning process itself.
Although the team was already working with these technologies before the chair was created, the University of Montpellier's Innovation and Partnerships Department (DIPA) helped put together the application for the ANR. "The DIPA was instrumental in helping us draft the application, calculate the budget, and give us tips on how to best present our research," adds Gilles Subra.
Convincing luxury professionals
The team now hopes to move upmarket. "We know that our technology can already be implemented in tanneries. Several of them are already using our process to train their employees. But we want to achieve a quality equivalent to that of chrome tanning in terms of flexibility, appearance, and feel, in line with the highest standards in leather goods. Luxury professionals are the biggest customers; if we can convince them, the whole industry will follow." The researchers also hope to improve the packaging and shelf life of silicic acid, which currently only remains stable for around two weeks in a container. Finally, they will continue to explore the use of leather scraps and the myriad possibilities for waste recovery: removing silicon to compost the remains, using the skin to make gelatin for animal feed, designing new composite materials based on unused pieces, or even transforming waste into biochar, a type of charcoal used in agriculture to capture water in arid soils and regulate pH.
In total, the team includes one full-time researcher, two doctoral students over four years, and 12 master's students on six-month research internships. Not to mention the staff of the associated laboratories and the eight people from the CTC group dedicated to the project, which has a total budget of €4.5 million, including €1.04 million specifically earmarked for the industrial chair as part of the call for projects. "If we make enough progress, we hope to see our first articles aimed at the general public as early as next year."