A number of model compounds resembling the fundamental bonding patterns of residual kraft lignin, including a series of stilbenes, were incubated with laccase from Trametes versicolor in the presence and absence of deligni®cation `mediators' ABTS and HBT. The condensed kraft lignin model compounds seem to undergo initial degradation by laccase mainly via benzylic oxidation, demethylation and hydroxylation reactions. Phenolic 5-50, diphenylmethane and a-5 lignin models were found to be degraded mainly via side-chain oxidation reactions. Among the models studied, a phenolic stilbene was found to be the most reactive, yielding several products showing side-chain oxidation/transposition, demethoxylation and hydroxylation reactions. Non-phenolic 5-50, diphenylmethane and stil- bene model compounds were found unreactive even in the presence of the laccase-mediator system.
|Titolo:||The early biodegradation steps of residual kraft lignin models with laccase|
|Data di pubblicazione:||1998|
|Appare nelle tipologie:||2.1 Articolo su rivista |
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