Investigation on the attack of Trichoderma viride on wheat straw composites manufactured with methylene diphenyl diisocyanate

Abstract

Trichoderma viride can infect wheat straw composites (WSC), thus affecting the quality of boards. This study investigated the change in color of the composite and its chemical composition after the straw was infested with mold with for 4, 8, or 12 weeks. Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) were used to analyze chemical structural changes in the WSC after the infestation. The infested surface and core layers were examined and analyzed. The infection of T. viride on the WSC can darken its color. After 12 weeks of cultural infestation, 19.6% of cellulose, 27.2% of xylan, 9.3% of lignin, and 31.9% of ethanol extracts were degraded. The degradation on WSC by T. viride was 9 times and 14 times more than the degradations of pine and poplar wood, respectively. T. viride attacked WSB differently on its surface and center layers. More lignin in the WSB surface layer was degraded. In contrast, cellulose and xylan were degraded to a greater degree in the center.