Quinone-hydroquinone formation, lignin

Quinone/Hydroquinone Formation. In studies on biodegradation of lignin models with ligninolytic cultures of P. chrysosporium (and other fungi), a number of quinones and hydroquinones were isolated. In other studies their formation has been implied from the isolation of their structural counterparts (29,30), where rapid fungal degradation of the quinones prevented their isolation. Various routes to these metabolic intermediates exist, which have been extensively reviewed (26,27). 

Side chain displacement with the formation of p-quinones and hydroquinones were the primary reactions observed. The product of oxidation by singlet oxygen was a function of the structure of the lignin model compound and the pH, as seen in Scheme 16.13. For example, vanillin, 43 produced methoxy-p-hydroquinone, 50... 

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