Lignin depolymerization is catalyzed by extracellular peroxidases of white-rot basidiomycetes such as Phanerochaete chrysosporium. In submerged culture, production of multiple lignin peroxidase (LiP) isozymes is derepressed under carbon, nitrogen, or sulfur limitation. The roles of the individual isozymes in lignin degradation and their genetic regulation are poorly understood (reviewed by Kirk and Farrell, 1987).