Enzymatic digestibility of ethanol pretreated wheat straw

Wheat straw was pretreated by sulfuric acid-catalyzed( SAC) and auto-catalyzed( AC) ethanol organosolv processes. The main chemical compositions,cellulose digestibility and ethanol production by hemi-simultaneous saccharification and fermentation( hSSF) of pretreated solids were compared. The results showed that SAC and AC pretreatments recovered more than 90% of cellulose as solid phase. Addition of non-ionic surfactants Tween 20 and Tween 80 did not significantly improve the enzymatic digestibility and ethanol production of SAC-pretreated wheat straw. However,they showed some positive effects on AC-pretreated wheat straw,with the corresponding enzymatic glucan conversion increased from 72. 7% to 85. 0% and ethanol concentration increased by 11. 4%. Material balance analysis showed that glucan recoveries,as a solid phase,were 91. 0% and 95. 4% for SAC and AC pretreatments,respectively. Corresponding ethanol yields were 10. 4 and 11. 6 g per 100 g raw material during SSF process,respectively.