What Else Can Collagen Do?
LASRA and Earth Sciences New Zealand are exploring an unexpected new use for chrome-tanned leather shavings.
The work began with a practical question from Tasman Tanning Ltd.: what more might be possible with chrome-tanned leather shavings generated during leather manufacture?
Chrome shavings are an established by-product of the tanning process. They contain a substantial collagen component, but the collagen has already been stabilised with chromium during tanning, which can make further use technically challenging. For Tasman, understanding whether this material could be put to a more productive use is a genuine industrial question.
That gave LASRA researchers an opportunity to look at the material from a different perspective — not by starting with a predetermined product, but by asking what useful properties the shavings already retained.
What if the chemistry already present in chrome shavings could make them useful?
From Waste Stream to Material
From shavings to a functional film
Rather than removing the chromium or extracting the collagen, LASRA researcher Zoheb Akhter used simple mechanical processing to turn the shavings directly into thin films.
Chrome shavings were mechanically processed, cast and dried to form a thin collagen film.
A Surprisingly Capable Material
The tanning chemistry was still doing its job
The films were thin enough to handle and cut, yet the untreated material reached an average tensile strength of 36.3 MPa without synthetic reinforcement.
The films also retained the thermal stability associated with chrome-tanned collagen. The untreated film showed a collagen denaturation temperature of 98.9 ± 0.4 °C, indicating that the stabilizing effect of chromium crosslinking was maintained following milling and film formation.
Synchrotron measurements at SOLEIL in France showed that the characteristic fibrillar periodicity of collagen was retained following tanning, milling and film formation.
Advanced Materials
Testing what else the material could do
Working with Earth Sciences New Zealand, the team began exploring whether these films could have functions beyond their mechanical and structural properties.
Energy storage provided one interesting test case. In laboratory experiments, the films were exposed to electrolyte to investigate their ability to support ion transport. The untreated collagen film achieved an ionic conductivity of 5.08 mS cm⁻¹, demonstrating that the material could support ionic conduction while retaining its physical form.
The simple version
The collagen network can hold an electrolyte. That electrolyte provides a pathway for ions to move through the material.
This is still research.
These experiments provide an early demonstration of the material’s potential, rather than pointing to a defined commercial application. Long-term wet-state durability remains an important challenge, and there is considerably more to learn about its performance.
The Bigger Question
Perhaps “waste” is the wrong place to start.
Chrome shavings are usually approached as a problem to treat, recover or dispose of. This research suggests another starting point: ask what useful properties the material already has.
Advanced materials are one possible direction. The larger opportunity is to understand collagen-rich leather-processing streams as materials whose structure and chemistry can be engineered for new functions.
Industry collaboration: Tasman Tanning Ltd.
Research led by Zoheb Akhter at LASRA in collaboration with Earth Sciences New Zealand and ISIS Neutron and Muon Source in the UK. Structural characterization included SAXS measurements at the SWING beamline of Synchrotron SOLEIL, France, with beamtime supported by the ReMade@ARI project.
The research was supported by the Ministry of Business, Innovation and Employment of New Zealand (MBIE) through grant LSRX-1801. The work has been presented at the 74th LASRA Conference in Auckland, August 2026.