Degradation of lipophilic wood extractive constituents in Pinus sylvestris by the white-rot fungi Bjerkandera sp. and Trametes versicolor

Abstract

The white-rot fungi Trametes versicolor and Bjerkandera spp. are among the most frequent decomposers of angiosperm wood in forest ecosystems and in wood products in service. Wood extractives have a major impact on wood properties and wood utilization. This work evaluated the ability of two white-rot fungal strains (Bjerkandera sp. strain BOS55 and T. versicolor strain LaVec94-6) to degrade the main lipophilic extractive constituents in Scots pine (Pinus sylvestris L.). The time course of wood decay and wood extractive degradation was monitored in stationary batch assays incubated for eight weeks. The strains tested eliminated high levels of total resin, 34 to 51% in two weeks. Wood triglycerides were the most readily degraded extractive components (over 93% elimination in only two weeks). Free fatty acids and resin acids, which are potential fungal inhibitors, were also rapidly decomposed by the fungal strains. Sterols were used more slowly, nonetheless, the fungal degradation of this extractive fraction ranged from 50 to 88% after four weeks.