As a white-rot basidiomycetous and wood-decaying fungus, Phlebiopsis gigantea (Fr.: Fr.) Jülich is able to degrade lignin, cellulose and hemicellulose with a complex set of extracellular enzymes. Enzyme activity of this fungus has not been sufficiently explored.

   The aim of this study was to assess the activity of laccase and peroxidases as well as the level of micromolecular compounds in P. gigantea strains, grown on pieces of Norway spruce wood (sapwood and heartwood) over 50 days of incubation under laboratory conditions. Enzymatic activity was determined using spectrophotometry. Phlebiopsis gigantea strains showed laccase (Lacc), manganese peroxidase (MnP), lignin peroxidase (LiP) and versatile peroxidase (VP) activity. Hydroxy– and methoxyphenols were released during this process as well. High levels of MnP activity (from 5.5 to 107.847 mU/μg of protein in cultures on sapwood and from 7.585 to 229.055 mU/μg of protein in cultures on heartwood) were observed in P. gigantea strains, as well as high activity of VP with manganese-oxidizing properties (from 3.36 to 61.708 mU/μg of protein on sapwood and from 1.7 to 254.479 mU/μg of protein on heartwood) compared with the other examined extracellular enzymes. Laccase and LiP activity were found to be low in all strains of P. gigantea as well as the activity of VP in terms of guaiacol-oxidizing properties (both on sapwood and heartwood samples).

Keywords: white-rot fungus, Phlebiopsis gigantea, laccase, manganese peroxidase, lignin peroxidase, versatile peroxidase, hydroxyphenols, methoxyphenols.