Degradation of Trimeric Lignin Model Compounds, Arylglycerol-β-syringaresinol Ethers, by Fusarium solani M-13-1

Abstract

Trimeric lignin model compounds, arylglycerol-β-syringaresinol ethers, were incubated with Fusarium solani M-13-1 in basal salts medium with shaking. From the culture filtrates, degradation products were isolated and characterized spectroscopically. Based on the degradation products of guaiacylglycerol-β-syringaresinol ether (II), the following reactions were found to occur; 1) oxidation of benzylic position (α′′) and subsequent ring opening of the syringaresinol side chain, 2) cleavage of alkyl-aryl C-C bonds (C_α-C₁ and C_α′′-C_1′′) of both arylglycerol and syringaresinol portions, and 3) splitting of the alkyl-aryl ether bond (C_β-O-C_4′). In the case of syringlyglycerol-β-syringaresinol ether (III), preferential oxidation of benzylic position (α) of the arylglycerol moiety was seen. The former two reactions were found to be catalyzed by the fungal phenol oxidizing enzymes.