Protease encapsulated liposomes for twin benefits: a green approach to unhairing and soft leather production.

Abstract

Rising ecological concerns are driving industries, including leather manufacturing, to adopt more sustainable practices. A major focus is transitioning from traditional chemical-based methods to bio-based alternatives. Enzyme-based unhairing has emerged as a potential replacement for the conventional lime-sulfide process. However, it faces challenges such as poor enzyme stability under harsh processing conditions, high cost, and possible grain damage resulting from uncontrolled enzymatic activity. Herein, we propose using egg-derived L-α-phosphatidylcholine (EPC) liposomes as protective carriers to encapsulate protease, aiming to improve its stability and efficacy during the unhairing process. Protease-loaded EPC liposomes (EPC+Pro) were synthesized and characterized for their size, zeta potential, thermal behavior, and morphology. The average size of EPC+Pro liposomes was 386 ± 10 nm with a zeta potential of -46 ± 0.1 mV. When applied to goat skin, EPC+Pro liposomes enabled complete (100%) hair removal within 3 h, while the unhairing process using free protease required 5 h to achieve comparable results. Beyond ensuring quick and efficient hair removal, EPC+Pro demonstrated a dual function by acting as a natural fatliquor, markedly enhancing the softness of leather with low fatliquor consumption. The treated leather showed a softness of 5.13 ± 0.2 mm, higher than the 4.26 ± 0.3 mm observed with free protease treatment. Overall, EPC+Pro treated leather demonstrated superior physical properties. This study highlights the potential of protease-encapsulated liposomes as a dual-functional, efficient, and sustainable solution for enzymatic unhairing, offering improved process efficiency, enhanced leather quality, and reduced chemical usage for commercial leather processing.