OXIDATIVE-DEGRADATION OF NONPHENOLIC LIGNIN DURING LIPID-PEROXIDATIONBY FUNGAL MANGANESE PEROXIDASE

A non-phenolic lignin model dimer, ethoxy-3-methoxyphenyl)-2-phenoxypr opane-1,3-diol, was oxidized by a lipid peroxidation system that consi sted of a fungal manganese peroxidase, Mn(II), and unsaturated fatty a cid esters. The reaction products included -3-methoxyphenyl)-1-oxo-2-p henoxy-3-hydroxypropane and (4-ethoxy-3-methoxyphenyl)-1-oxo-3-hydroxy propane, indicating that substrate oxidation occurred via benzylic hyd rogen abstraction. The peroxidation system depolymerized both exhausti vely methylated (non-phenolic) and unmethylated (phenolic) synthetic l ignins efficiently. It may therefore enable white-rot fungi to accompl ish the initial delignification of wood.