Eco-dyeing of wool with polyphenols based on immobilized laccase-catalyzed oxidative polymerization

Abstract Colouration is a crucial aspect of textile manufacturing, enhancing the appearance and appeal of fabrics. However, conventional wool dyeing relies on synthetic dyes, chemical auxiliaries, and high-temperature processes (95–100 °C), leading to significant environmental concerns such as excessive water consumption, chemical pollution, and high energy demands. This study explores the in-situ colouration of wool textiles using native and immobilized laccase at a lower temperature of 50 °C, offering a sustainable alternative aligned with the principles of green chemistry. The enzymatic process enabled the development of a diverse colour palette through oxidative polymerization of aromatic compounds (catechol and aminophenol) using laccase catalysis. The 2% laccase concentration at pH 5–6 with a minimum reaction time of 4 h yielded high colour depth on wool samples, with maximum K/S values of 4.65 for catechol and 10.61 for aminophenol. The immobilized laccase could be reused for 3–4 dyeing cycles with equivalent colour strength to native laccase for both the precursors. The dyed samples exhibited good washing fastness (grade 4) and dry rubbing fastness (grade 4–5), meeting industry standards. Compared to conventional high-temperature acid dyeing, this enzymatic approach reduces energy consumption and chemical inputs while enabling enzyme recovery and reuse, thereby demonstrating its potential as a resource-efficient strategy for sustainable textile colouration.