Activation of thermomechanical pulp by laccases as studied by UV-Vis, UV resonance Raman and FTIR spectroscopy

The changes in lignin structure of spruce thermomechanical pulp (TMP), induced by treatment with laccase of Trametes hirsuta (ThL) and laccase of Melanocarpus albomyces (MaL), has been investigated by UV-Vis, UV resonance Raman (UVRR), and Fourier transform infrared (FTIR) spectroscopy. The spectroscopic results showed that the structural changes were small; however, the changes were slightly more pronounced in the case of MaL. Nevertheless, the brightness of the pulps remained higher after treatment with MaL than after treatment with ThL. Accordingly, MaL is a promising enzyme for fiber activation and functionalization