Evidence for cleavage of lignin by a brown rot basidiomycete

Summary Biodegradation by brown-rot fungi is quantitatively one of the most important fates of lignocellulose in nature. It has long been thought that these basidi­ omycetes do not degrade lignin significantly, and that their activities on this abundant aromatic biopolymer are limited to minor oxidative modifications. Here we have applied a new technique for the complete solu­ bilization of lignocellulose to show, by one-bond 1 H- 13 C correlation nuclear magnetic resonance spec­ troscopy, that brown rot of spruce wood by Gloeo­ phyllum trabeum resulted in a marked, non-selective depletion of all intermonomer side-chain linkages in the lignin. The resulting polymer retained most of its original aromatic residues and was probably inter­ connected by new linkages that lack hydrogens and are consequently invisible in one-bond 1 H- 13 C corre­