Mediator role of veratryl alcohol in the lignin peroxidase-catalyzed oxidative decolorization of Remazol Brilliant Blue R

Lignin peroxidase (LiP) produced by Trametes versicolor decolorizes Remazol Brilliant Blue R (RBBR) in the presence as well as in the absence of veratryl alcohol (VA). VA enhances and stabilizes the RBBR-decolorization rates by lignin peroxidase. RBBR has better substrate reactivity than VA for LiP. RBBR is also decolorized directly by LiP and competitively inhibits VA oxidation by LiP. In the presence of higher concentrations of RBBR (i) RBBR decolorization rates improve, (ii) veratryl aldehyde appears after a lag and (iii) VA oxidation rates decrease. The lag is due to consumption of VA cation radical (VAradical dot+) generated upon LiP-catalyzed VA oxidation, during RBBR oxidation. That may result in the formation of compound III in the absence of VAradical dot+ and contributes to the inhibitory influence of RBBR on LiP activity.