Polyoxometalate/laccase-mediated oxidative polymerization of catechol for textile dyeing

The synergistic effect between polyoxometalates (POMs), namely K ₅[SiW₁₁V^VO₄₀]•11H₂O and H₅[PMo₁₀V^V ₂O ₄₀]•13H₂O and laccase from ascomycete Myceliophthora thermophila has been employed for the first time in oxidative polymerization of catechol. Such a laccase-mediator system allowed the formation of a relatively high molecular weight polycatechol as confirmed by size exclusion chromatography and electrospray ionization mass spectrometry (ESI-MS) (3990 Da when using K₅[SiW₁₁V^VO₄₀]•11H ₂O and 3600 Da with H₅[PMo₁₀V^V ₂O₄₀]•13H₂O). The synthesized polymers were applied as dyes for the dyeing of flax fabrics. The color intensity of flax fabrics colored with polymer solutions was evaluated by diffuse reflectance spectrophotometry via k/s measurements (+10% of fixation ratio). A new synthetic process allowed a dyeing polymer, provided upon flax coloration, better color fixation and color resistance when compared to that obtained by conventional synthesis with laccase solely or with addition of organic mediator (1-hydroxybenzotriazole).