Veratryl alcohol oxidation cleavage

D Annibale and his colleagues [99] performed experiments on VA oxidation using MnP from Lentinus edodes. They demonstrated two different types of reactions occurring in the presence and absence of GSH. When GSH was not included in the reaction mixture of MnP, Mn +, VA, H2O2 and chelator, aromatic ring cleavage, side chain oxidization and dimerization of VA were detected. (The main metabolite was y-muconolactone (58%), and three dimerization products were also observed [31] 2.3 and 1.8%, respectively). However, with the addition of GSH, veratraldehyde was the only metabolite formed. Veratryl alcohol oxidation was 32 and 14% in nonthiol and thiol mediated reactions, respectively. Under both conditions, oxidation depended strictly on the presence of both Mn + and H2O2. 

LiP catalyzes the oxidation of a low-molecular-weight redox mediator, veratryl alcohol, which in mrn mediates one-electron oxidation of lignin to generate aryl cation radicals [100]. The radicals facilitate a wide variety of reactions such as carbon-carbon cleavage, hydroxylation, demethylation, and so on. Dezotti et al. [101] reported enzymatic removal of color from extraction stage effluents using lignin and horseradish peroxidases immobilized on an activated silica gel support. 

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