Changes in chemical composition of decayed Scots pine and beech wood

Abstract

In this study, changes in chemical composition of aged and unaged Scots pine and beech wood decayed by brown-rot fungi Coniophora puteana and Poria placenta were presented by Fourier transform infrared (FT-IR) spectra. Samples were exposed to six complete cycles of accelerated aging for 12 days and then subjected to brown-rot fungi attack for 8 weeks. Weight loss of samples was found to be 25-46% depending on wood and fungi species and being aged ones. Accelerated aging treatments seemed to have a slight role on chemical composition of Scots pine and beech samples while they increased biodegradation of samples. FT-IR spectra showed degradation of wood carbohydrates revealed by reduction of the peaks responsible for hemicellulose and cellulose at 1730, 1370, 1150, and 897 cm(-1) in pine and 1730, 1370, 1027, and 897 cm(-1) in beech. Stronger lignin peaks at 1650, 1593, 1506, 1455, 1422, 1261, and 1230 cm(-1) in pine and 1650, 1506, 1455, and 1422 cm(-1) in beech were obtained after decay test. FT-IR spectra of samples were consistent with the degradation mechanism of brown-rot fungi. In general, changes in the carbohydrate and lignin peaks were greater in samples exposed to accelerated aging treatments for both wood species.