Carbohydrate-dependent Enzymic Quinone Reduction during Lignin Degradation.

Abstract

Indications for the existence of a new enzyme were obtained when Polyporus versicolor, a white-rot fungus, was grown on lignin agar plates supplemented individually with glucose, cellobiose or cellulose. Formation of chromophoric structures occurred through the action of a polyphenol oxidase (laccase) but was ef ¬ fectively reversed when cellulose was present in the agar plates. Under these conditions the fungus produced an extracellular enzyme which, in the presence of cellobiose, reduced the stable quinone tested, namely 3-methoxy-5-tert-butylbenzoquinone-(l,2). The enzyme together with cellobiose inhibited phenolic coupling of guaiacol by laccase and although oxygen consump¬ tion proceded normally no polymeric products were formed.