Revealing the degradation process of Moso bamboo (Phyllostachys edulis) by different decay fungi

Moso Bamboo (Phyllostachys edulis) is the main bamboo species for engineering; however, it is highly susceptible to various fungi during use. In this study, four prevalent decay fungi, including two brown rot fungi and two white-rot fungi, were used as the test fungi to investigate the changes in structure and chemical composition of Moso bamboo samples at different incubation times in order to better understand the degradation mechanism of the decay fungi on bamboo. Mass loss, pH, and moisture content of Moso bamboo after fungal incubation showed regular changes, while the crystallinity of the bamboo did not vary with the decay time and mass loss. Trametes versicolor caused the highest mass loss up to 55.5% while Postia placenta caused only 19.8% after a 16-week incubation. The bamboo incubated in T. versicolor had a relative crystallinity of 59.72 and pH of 4.06 after a 16-week incubation, while the bamboo incubated in Gloeophyllum trabeum had a relative crystallinity of 45.09 and a pH of 3.71. Scanning electron microscopy showed that brown-rot fungi degraded the vessels, followed by the fibres, the white-rot fungi degraded the vessels and possibly the parenchyma afterwards, thereby leading to an increase in the crystallinity of bamboo. The results of chemical composition analysis and XPS further proved that the degradation of bamboo by T. versicolor was a selective degradation pattern, which would provide great implications for the bioavailability of bamboo timber.