Comparison between degradation capabilities of the white rot fungi Pleurotus ostreatus and Trametes versicolor in beech wood

Abstract

The degradation capabilities of two white rot fungi, Pleurotus ostreatus and Trametes versicolor, obtained from natural stands of Fagus orientalis (beech) in Northern Iran were studied. Fruiting bodies of P. ostreatus and T. versicolor were collected from fallen beech in the Alamdardeh forest, Iran. Beech wood samples were exposed to both fungi for 120 days according to EN113. Mass loss, resistance to compression parallel to grain, impact load resistance, as well as lignin, cellulose and hemicellulose content were determined in the samples before and after fungal exposure. FT-IR spectroscopy was used to collect spectra after fungal decay. Light and electron microscopy were used to study white-rot decay patterns in wood and compare the mechanism of attack for both fungi. Both fungi reduced wood mass and chemical constituents in similar quantities. Chemical analyses indicated similar reductions in cellulose, lignin and total carbohydrates. Both fungi had negligible affect on the hemicelluloses, arabinan, galactan, and glucan. Patterns of white decay were the same for both fungi. Thinning of the cell walls, colonization of fungal hyphae as well as formation of bore holes on the cell wallswere also similar for both fungi. The results demonstrated that both fungi produced a simultaneous white rot in beech wood.