DEMONSTRATION OF LACCASE IN THE WHITE-ROT BASIDIOMYCETE PHANEROCHAETE-CHRYSOSPORIUM BKM-F1767

It has been widely reported that the white rot basidiomycete Phaneroch aete chrysosporium, unlike most other white rot fungi, does not produc e laccase, an enzyme implicated in lignin biodegradation, Our results showed that P. chrysosporium BKM-F1767 produces extracellular laccase in a defined culture medium containing cellulose (10 g/liter) and eith er 2.3 or 23 mM ammonium tartrate. Laccase activity was demonstrated i n the concentrated extracellular culture fluids of this organism as de termined by a laccase plate assay as well as a spectrophotometric assa y with ABTS [2,2'-azinobis(3-ethylbenzathiazoline-6 acid)] as the subs trate. Laccase activity was observed even after addition of excess cat alase to the extracellular culture fluid to destroy the endogenously p roduced hydrogen peroxide, indicating that the observed activity is no t due to a peroxidase, Sodium dodecyl sulfate-polyacrylamide gel elect rophoresis followed by activity staining with ABTS revealed the presen ce of a laccase band with an estimated M(r) of 46,500.