ROLE OF LACCASE IN LIGNIN DEGRADATION BY WHITE-ROT FUNGI

Laccase is commonly found in white-rot fungi and catalyses the abstraction of one electron from the phenolic hydroxyl group to polymerize or depolymerize lignin model compounds, Laccase degrades both beta-1 and beta-0-4 dimers via C-alpha-C-beta cleavage, C-alpha oxidation and alkyl-aryl cleavage. Also, aromatic ring cleavage may be detected following the action of laccase. Laccase can also oxidize non-phenolic compounds when primary mediators, such as 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate), are co-present, Laccase produces Mn(III) chelates which allow wood-decaying enzymes to penetrate wood cell walls. Laccase is considered to be capable of degrading lignin together with lignin peroxidase and manganese peroxidase.