Valorization of tannery-derived FAMEs into bio-based epoxides via chemo-enzymatic synthesis

Abstract

The urgent transition toward low-carbon chemical manufacturing has prompted the development of renewable alternatives to fossil-based epoxy intermediates. This study presents an integrated and resource-efficient chemoenzymatic route for the synthesis of epoxidized methyl oleate (EMO) from fatty acid methyl esters (FAMEs) derived from tannery waste—a lipid-rich but underutilized industrial residue. A single-step urea complexation achieved 86.7 ± 0.6 % methyl oleate purity with a 38.1 ± 0.9 % recovery yield, while the saturated-rich coproduct (~40 %) exhibited physicochemical properties suitable for biodiesel or lubricant applications. Subsequent epoxidation was carried out using immobilized Candida antarctica lipase B (Novozym® 435) and in situ generated performic acid, yielding an oxirane oxygen content of 6.42 ± 0.14 %, corresponding to >90 % conversion of double bonds under mild conditions. The enzyme retained 72 % of its initial activity after ten reuse cycles, significantly enhancing process circularity and reducing catalytic costs. Green chemistry metrics were favorable: atom economy reached 86 %, solvent recovery exceeded 85 %, and the E-factor remained as low as 0.86 kg waste/kg EMO. A cradle-to-gate life cycle assessment (LCA) estimated a global warming potential (GWP) of 1.92 kg CO₂-eq/kg EMO—representing a 63 % reduction compared to petrochemical benchmarks. Economic analysis at the 1000 t/year scale yielded a production cost of €1.57/kg with an internal rate of return (IRR) of 15 %. Overall, this work demonstrates how lipid-rich industrial residues can be converted into high-value bio-based epoxides through a scalable and environmentally sound chemo-enzymatic route, aligning with circular economy principles and green chemistry targets.

The authors gratefully acknowledge the collaboration and technical support provided by the CORIUM Project team and Leather Cluster Barcelona throughout the development of this research. This study was funded by the Catalonia Clusters Program for Business Competitiveness Reinforcement (Project ACE103/23/000033), with support from ACCI\u00D3 \u2013 Government of Catalonia. This work was supported by the CORIUM project (Valorization of triacylglycerides extracted from leather fleshing), funded through the 2023 Catalonia Clusters Program for Business Competitiveness Reinforcement (Project reference: ACE103/23/000033 ), with financial support from ACCI\u00D3 \u2013 Government of Catalonia .