Biodegradation of treated softwood and hardwood species by brown rot fungi

The aim of this study was to investigate enzymatic activity and biodegradation capacity of treated wood by three brown rot fungi. For measurement of enzymatic activity, the brown rot fungi Coniophora puteana, Postia placenta and Gloeophyllum trabeum were grown in solid state fermentation of wheat bran-containing medium. The highest enzymatic activity of all enzymes, i.e. 8.3 U mL –1 , was detected for C. puteana-produced xylanase. The highest activity of endoglucanase, i.e. 4.4 U mL –1 , was detected for P. placenta. Total cellulolytic activity showed the lowest value (0.1 U mL–1) for all the fungi under study. To improve the durability of softwoods, they were impregnated with wood preservatives Celcure AC 500 and Dikants and hydrothermally modified in two regimes, 150 °C for 3 h and 160 °C for 1 h. Hardwoods were hydrothermally modified at 160 °C for 1 h. The efficiency against softwood degradation by C. puteana, G. trabeum and P. placenta and that against hardwood degradation by C. puteana were determined according to the standards CEN/TS 15083-1 and EN 84. Heat treatment was more effective than chemical treatment. Hydrothermal modification by the same conditions (temperature/time) was more effective for softwoods than hardwoods.