Biodegradation of cotton stalk by three white rot fungi and the effects on composition and structure changes of cotton stalk

In recent years, fungal pretreatment has received renewed attention for biorefinery of lignocellulosic feedstock. The present research was aimed to examine the biodegradation effects of three white rot fungi on cotton stalk. The results showed that three white rot fungi could degrade the lignocellulose of cotton stalk effectively at a certain degradation stage, the forming ratio of hyphal protein had significant negative correlation at the 0.01 level with hemicellulose and cellulose contents in biodegradation process; the degradation period was determined as 15 days, and Phanerochaete chrysosporium was chosen as the main strain for cotton stalk biodegradation. The analysis of FTIR (Fourier transform infrared spectroscopy) and SEM (Scanning electron microscopy) revealed that the intensity of absorption peaks of lignin, cellulose and hemicellulose decreased in 15-day degraded samples compared to original sample, especially the lignin related groups were degraded strongly, which demonstrated that all the three white rot fungi degraded the cotton stalk lignin effectively; correspondingly, the hypha of white rot fungi entered inside the lignocellulose of cotton stalk, and destroyed the structure, forming many cracks and holes, which exhibited good breaking and extending capability.