Decomposition of specifically 14C-labelled phenols and dehydropolymers of coniferyl alcohol as models for lignin degradation by soft and white rot fungi

Abstract

Several soft and white rot fungi were compared in their ability to degrade specifically 14C-labelled phenols and dehydropolymers of labelled coniferyl alcohol. Furthermore, plant material, which was expected to be specifically labelled in the lignin part was used in the degradation studies. The experiments showed that both groups of fungi were able to release CO2 from methoxyl and carboxyl groups of phenol-carboxylic acids, to degrade side chains of cinnamic acids and cinnamyl alcohols and even to decompose aromatic structures. With the dehydropolymers and the plant material a CO2 release from the methoxyl groups, the side chains and the aromatic carbons was observed. The time dependant course of the CO2 release from these different groups showed in the beginning a higher CO2 evolution from the side chain carbons than from the methoxyl groups, which were later on released to a higher extent. No laccase activity could be detected in the soft rot fungi and the peroxidase activity was lower than in the white rot fungi.