Cellulose enzymatic hydrolysis of wheat straw after solid-state pretreatment by Trametes trogii: a factorial study.

Practical use of the polysaccharidic fraction of lignocellulosic material is limited by its high lignin content. In this study the lignin-degrading white-rot fungus Trametes trogii Berk. in Trog. was used in the solid-state pre-treatment of wheat straw and the efficiency of the enzymatic hydrolysis of the residual cellulose after pre-treatment was analysed. Glucose, mineral nitrogen and yeast extract were used to supplement the pre-treatment minimal medium. Results were determined on the basis of levels of glucose and total reducing sugars released after batch incubation with foreign cellulases. The principal effect of medium components, as well as the effects of their interaction, were investigated using a two-level full factorial analysis in function of pre-treatment and hydrolysis times. Evidence is provided to show that better results are obtained in the presence of glucose, while the presence of nitrogen sources results in lower yields irrespective of the time course of the process. Key words: Trametes trogii, lignin, bioconversion, white-rot, straw-degradation.