Hydrolytic enzyme activity of EN113 standard basidiomycetes in the fermentation of lignocellulosic material and wood colonization

Abstract

Abstract The white-rot fungus Trametes versicolor and brown-rot fungi Coniophora puteana, Gloeophyllum trabeum, and Postia placenta have a potential to produce a range of hydrolytic enzymes participating in the degradation of lignocellulosic materials. In the colonization of untreated and thermally modified wood blocks wheat bran-containing medium (WBA) greatly favored the secretion of xylanase by C. puteana and both endoglucanase and xylanase expression by T. versicolor, although rather higher carboxymethyl cellulase activity of C. puteana was observed on the malt extract-based medium (malt extract-containing agar (MEA). Coniophora puteana and T. versicolor are able to actively colonize and degrade the untreated pine and birch wood blocks. The mycelium applied on blocks in the form of pellets was more aggressive in wood degradation in comparison with the colonized mycelium. WBA favored the dry matter loss during the initial stages (10–20 days) of pine wood colonization; however, MEA further promoted more rapid wood degradation. The main finding was that the thermal treatment of birch wood was accompanied by a low degree of fungal colonization and increased durability against the fungal attack in spite of the high cellulase and xylanase activities. Thermal modification of wood was not toxic to the fungi because it did not disturb the secretion of the hydrolytic enzymes involved in wood degradation. The thermally modified hollocellulose is probably less susceptible to the enzymes involved in the degradation of polysaccharides or less accessible to hydrolytic enzymes due to the change of the cell wall structure.