Chromium(III) tanning remains the dominant leather manufacturing technology due to rapid processing, excellent hydrothermal stability, and balanced mechanical properties, but is increasingly associated with environmental and health concerns. Existing chrome‑free tanning systems often fail to simultaneously provide high thermal stability, mechanical strength, and environmental compatibility. Here, we report a bio‑inspired dual crosslinking strategy that integrates plant‑derived polyphenols with enzyme‑activated in situ carbonyl generation to stabilize collagen fibers without metals or externally added aldehydes. Polyphenols initially stabilize collagen via hydrogen bonding and hydrophobic interactions, while laccase‑catalyzed oxidation generates reactive carbonyl intermediates within the matrix, enabling covalent crosslink formation under mild conditions. Sheep skin leathers produced using this system exhibited shrinkage temperatures up to 96 0C, tensile strength of 19 N mm⁻², and 18 % higher water vapor permeability than chrome‑tanned controls. Effluent chemical oxygen demand (COD) and biological oxygen demand (BOD) were reduced by approximately 58 %, and chromium‑containing solid wastes were eliminated. The process demonstrates chrome‑like performance via enzyme‑generated crosslinks, offering a sustainable and industrially compatible pathway for leather manufacture.
Teklay Asgedom Teferi (PhD)2* Woldeamanuel Wondaferash Atinafu (MSc)1 (Tue,) studied this question.