Effects of Incubation Conditions on Degradation of Bamboo Chips by White-rot Fungi Trametes hirsute

摘要

Fungal pretreatments were carried out under highly controlled incubation conditions where constant temperature and relative humidity were maintained and aeration was supplied.The ability of white-rot fungi to selectively degrade lignin was significantly influenced by these culture conditions.In this research the degradation process of bamboo chips using white-rot fungi Trametes hirsuta 19-6 and 19-6(w)was performed,and especially the effects of selective delignification using different culture conditions such as initial pH and temperature,style of ventilation,and addition of nutrients,were investigated.Based on the changes of the chemical compositions of the bamboo chips after fungal treatment,the optimal temperature and the optimal pH were found to be 28°C and pH 4.5,respectively,for the Trametes hirsute 19-6and 19-6(w)treatments.The highest degradation of lignin was achieved for Trametes hirsuta 19-6 and 19-6(w)with oxygen supplied and nutrients added.At the same time,degradation of lignin always occurred together with the degradation of cellulose and hemieellulose.It was concluded from the experiment that addition of nutrient with appropriate adjustment of pH,appropriate temperature and oxygen supply would increase the degree of delignification.The research also showed that white-rot fungus Trametes hirsuta 19-6 gave better results than 19-6(w)on the degree of bamboo lignin degradation.