LACCASE IS ESSENTIAL FOR LIGNIN DEGRADATION BY THE WHITE-ROT FUNGUS PYCNOPORUS-CINNABARINUS

The white-rot fungus, Pycnoporus cinnabarinus, provides an excellent m odel organism to elucidate the controversial role of laccase in lignin degradation, P, cinnabarinus produces laccase in one isoform as the p redominant phenoloxidase in ligninolytic cultures, and neither LiP nor MnP are secreted, Yet, P, cinnabarinus degrades lignin very efficient ly, In the present work, we show that laccase-less mutants of P, cinna barinus were greatly reduced in their ability to metabolize C-14 ring- labeled DHP, However, (CO2)-C-14 evolution in these mutant cultures co uld be restored to levels comparable to those of the mild-type culture s by addition of purified P, cinnabarinus laccase, This clearly indica tes that laccase is absolutely essential for Lignin degradation by P, cinnabarinus. (C) 1997 Federation of European Biochemical Societies.