Table 5. Chemical mechanism of laccase-catalyzed oxidation of different substrates.

Substrate	Mechanism	Reference
GUA	Generation of phenoxyl radical followed by co-oligomerization	[41]
ABTSa	Generation of ABTS+• and then ABTS2+; mediation via an electron transfer mechanism	[37], [43]
HBTa	Generation of nitroxyl radical (>N–O•); mediation via a hydrogen atom transfer mechanism	[37], [43]
TEMPOa	Generation of oxoammonium ion (>N = O+); mediation via a non-radical-ionic mechanism	[37], [43]
Azo dyes	Abstract of one electron to generate phenoxyl radical; abstract of a second electron to yield an aromatic cation	[48]
Triarylmethane dyes	Successive demethylation/deethylation by laccases; hydroxylation of dye to form carbinol followed by successive oxidation by LMSs	[49]
Indigoid dyes	Formation of dehydroindigo followed by nucleophilic attack by water molecules	[50]
Anthraquinone dyes	Single electron oxidation of secondary amine to imine followed by nucleophilic attack by water molecules	[51], [52]

^aLaccase mediators.