Comparison of the Decay Behavior of Two White-Rot Fungi in Relation to Wood Type and Exposure Conditions.

Ehsan Bari,Jong Sik Kim,Nural Yilgor,Geoffrey Daniel,Adya P Singh,Javier Ribera,Mohammad Ali Tajick-Ghanbary

doi:10.3390/microorganisms8121931

Abstract

Fungal wood decay strategies are influenced by several factors, such as wood species, moisture content, and temperature. This study aims to evaluate wood degradation characteristics of spruce, beech, and oak after exposure to the white-rot fungi Pleurotus ostreatus and Trametes versicolor. Both fungi caused high mass losses in beech wood, while spruce and oak wood were more resistant to decay. The moisture content values of the decayed wood correlated with the mass losses for all three wood species and incubation periods. Combined microscopic and chemical studies indicated that the two fungi differed in their decay behavior. While T. versicolor produced a decay pattern (cell wall erosion) typical of white-rot fungi in all wood species, P. ostreatus caused cell wall erosion in spruce and beech and soft-rot type I (cavity formation) decay in oak wood. These observations suggest that P. ostreatus may have the capacity to produce a wider range of enzymes/radicals triggered by the chemical composition of wood cell walls and/or local compositional variability within the cell wall.

Highlights

The three classes of fungi, which attack woody materials, are Basidiomycetes, Ascomycetes, and Deuteromycetes [1]
The results presented here on wood decay by T. versicolor and P. ostreatus are based on a comprehensive study, employing relevant chemical and microscopic techniques, and extend the knowledge on the influence of wood species on the behavior of white-rot fungi
Average mass loss (ML) and moisture content (MC) for P. ostreatus and T. versicolor are shown in Figures 1 and 2

Summary

Introduction

The three classes of fungi, which attack woody materials, are Basidiomycetes, Ascomycetes, and Deuteromycetes [1]. Brown, and soft-rot fungi are the major groups of microorganisms capable of degrading wood cell walls to different levels and utilizing cell wall components. Brown- and soft-rot fungi utilize carbohydrates at different rates and produce different decay patterns [2]. Soft-rot fungi degrade wood cell walls, producing two morphologically different decay patterns known as Type I (cavity formation) and Type II (cell wall erosion) [3,4]. White-rot fungi produce simultaneous and selective decay patterns [6]. In both types of decay, the cell wall is degraded by fungal hyphae growing within the cell lumina, and cell wall degradation progresses from the lumen outwards. Tracking and monitoring the biological behavior of white-rot fungi has been undertaken under natural conditions [16,17,18], as well as under controlled conditions on unmodified [19,20,21,22,23] and modified wood [24]

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