Demonstration of Laccase in the White Rot Basidiomycete Phanerochaete chrysosporium BKM-F1767

Abstract

It has been widely reported that the white rot basidiomycete Phanerochaete chrysosporium, unlike most other white rot fungi, does not produce 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 either 2.4 or 24 mM ammonium tartrate. Laccase activity was demonstrated in the concentrated extracellular culture fluids of this organism as determined by a laccase plate assay as well as a spectrophotometric assay with ABTS [2,2-azinobis(3-ethylbenzathiazoline-6-sulfonic acid)] as the substrate. Laccase activity was observed even after addition of excess catalase to the extracellular culture fluid to destroy the endogenously produced hydrogen peroxide, indicating that the observed activity is not due to a peroxidase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by activity staining with ABTS revealed the presence of a laccase band with an estimated M r of 46,500.

Physiology of exolaccase production by Thelephora terrestris

“…The secretion of laccase by the ectomycorrhizal fungus T. terrestris was biomass-dependent as observed by Freitag and Morrell [18] in lignocellulolytic fungi. Residual glucose levels were demonstrated to be proportional to carbon source concentration, suggesting that secretion was not regulated by catabolic repression as previously suggested for Phanerochaete chrysosporium [6].…”

“…Extracellular ammonium was completely depleted at 72 h of growth and mycelial dry weight became stationary at the same time. The level of exolaccase activity was proportional to the ammonium concentration in the medium as was observed with the production of laccase by ligninolytic fungi [6,7,24]. The results from changing the nutrient ratio indicate that nitrogen limitation a¡ected laccase production ( Table 2) and mycelial growth.…”

“…The expression of laccase in T. terrestris was regulated by a low C/N ratio in spite of the growth rate. High C/N ratios increased the production of laccase in Pycnoporus cinnabarinus [21] whereas in Lentinus edodes [24], Phanerochaete chry-soporium [6] and Phanerochaete £avido-alba [7] the opposite was observed.…”

Biochemical and molecular characterization of a laccase from the edible straw mushroom, Volvariella volvacea

“…Basidiomycetes typically produce multiple laccase isoforms [5,[23][24][25][26][27][28][29] and V. volvacea produces at least two protein bands with laccase activity when grown in submerged culture under different conditions [1]. Previous physiological studies have shown that, as in other basidiomycetes, laccase production by V. volvacea is induced by copper and by various aromatic compounds.…”

Solid state fermentation and crude cellulase based bioconversion of potential bamboo biomass to reducing sugar for bioenergy production

“…However, P. chrysosporium is well reported for its high peroxidase enzyme (both LiP and MnP) activities associated with its lignin biodegradation. [24][25][26] Maximum laccase enzyme production of 70-80 U mL −1 by white rot fungus Panaeolus sphinctrinus using ABTS as substrate was also previously reported. 26,27 Our findings showed relatively much higher laccase production by L. elegans WDP2 in the minimal salt medium containing glucose and veratryl alcohol (as inducers).…”