AbstractThe emergence of novel high-speed inkjet printing technology has been hindered because of claims of poor deinkability of the printed product. Based on our results the decolorization of inkjet inks with the laccase-mediator system is a possible approach to improve the deinkability of inkjet-printed paper. The commercial Myceliophtora thermophila and Trametes versicolor laccases (1 U/mL) and a mediator compound acetosyringone (0.1 mM) decolorized water-soluble textile and inkjet ink dyes by up to 94% and aqueous dye-based inkjet inks by 40 to 98%. M. thermophila laccase decolorized magenta and black inks effectively even at pH 9.0. Acetosyringone was a better mediator compared to ABTS and violuric acid because of its high efficiency and low inherent color. The enzymatic decolorization of inkjet ink was also achieved in deinking experiments with inkjet-printed paper. A treatment with M. thermophila laccase (2 U/g of paper) and acetosyringone (0.02% of paper weight) improved ISO-brightness of the pulp by 5%.