We studied the effect of manganese and various organic chelators on the distribution, depolymerization, and mineralization of synthetic 14C-labeled lignins (DHP) in cultures of Phanerochaete chrysosporium. In the presence of high levels of manganese [Mn(II) or Mn(III)], along with a suitable chelator, lignin peroxidase (LiP) production was repressed and manganese peroxidase (MnP) production was...

Fungal secretory peroxidases mediate fundamental ecological functions in the conversion and degradation of plant biomass. Many of these enzymes have strong oxidizing activities towards aromatic compounds and are involved in the degradation of plant cell wall (lignin) and humus. They comprise three major groups: class II peroxidases (including lignin peroxidase, manganese peroxidase, versatile p...

A versatile ligninolytic peroxidase has been cloned from Pleurotus eryngii and its allelic variant MnPL2 expressed in Aspergillus nidulans, with properties similar to those of the mature enzyme from P. eryngii. These include the ability to oxidize Mn(2+) and aromatic substrates, confirming that this is a new peroxidase type sharing catalytic properties of lignin peroxidase and manganese peroxid...

Two methods were used to compare the biodegradation of six polychlorinated biphenyl (PCB) congeners by 12 white rot fungi. Four fungi were found to be more active than Phanerochaete chrysosporium ATCC 24725. Biodegradation of the following congeners was monitored by gas chromatography: 2,3-dichlorobiphenyl, 4,4'-dichlorobiphenyl, 2,4',5-trichlorobiphenyl (2,4',5-TCB), 2,2',4,4'-tetrachlorobiphe...

The oxidation of fluorene, a polycyclic hydrocarbon which is not a substrate for fungal lignin peroxidase, was studied in liquid cultures of Phanerochaete chrysosporium and in vitro with P. chrysosporium extracellular enzymes. Intact fungal cultures metabolized fluorene to 9-hydroxyfluorene via 9-fluorenone. Some conversion to more-polar products was also observed. Oxidation of fluorene to 9-fl...

5 White-Rot Basidiomycetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 5.1 Mineralization of 14C-Labeled Lignins . . . . . . . . . . . . . . . . . . . . . . . 141 5.2 Ligninolytic Enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 5.2.1 Lignin Peroxidase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 5.2.2 Manganese Perox...

It has long been known that manganese is an essential micronutrient of plants. Although the precise functions of manganese are unknown there is evidence that it may be concerned in chlorophyll synthesis, photosynthesis, respiration and nitrate assimilation. Decreased photosynthesis under conditions of manganese deficiency was originally attributed to the diminished chlorophyll content, but more...

Manganese peroxidase, produced by some white-rot fungi during lignin degradation, catalyzes the oxidation of Mn2+ to Mn3+. Whereas Mn3+ is known to oxidize phenolic compounds, its role in lignin degradation is not clear. We have used a series of methoxybenzenes with E1/2 values of 1.76-0.81 V (vs saturated calomel electrode) to investigate the oxidizing ability of Mn3+ chelates generated chemic...

The abilities of whole cultures of Phanerochaete chrysosporium and P. chrysosporium manganese peroxidase-mediated lipid peroxidation reactions to degrade the polycyclic aromatic hydrocarbons (PAHs) found in creosote were studied. The disappearance of 12 three- to six-ring PAHs occurred in both systems. Both in vivo and in vitro, the disappearance of all PAHs was found to be very strongly correl...