Detoxification and Ethanol Fermentation of the Acid-catalysed Steam-exploded Corn Stover Pre-hydrolyzate

The pre-hydrolyzate obtained from the acid-catalysed steam-exploded corn stover( ASC) after washing with water was used as the raw material. The contents of fermentable sugars,carbohydrate degradation products and main lignin degradation products in the ASC pre-hydrolyzate were analyzed. The ethanol fermentation performance of the ASC pre-hydrolyzate before and after detoxification by three kinds of detoxification methods was also investigated. The results indicated that the ASC prehydrolyzate contained fermentable sugars including xylose( 49. 50 g /L) and few glucose( 9. 80 g /L),which could be fermented to produce ethanol. However,it was not beneficial to ethanol fermentation because of the existed inhibitors. The sugar utilization ratio and ethanol yield were only 87. 96 % and 74. 63 %,respectively,after 60 h fermentation. The ethanol fermentation of the ASC pre-hydrolyzate was greatly improved after the ASC pre-hydrolyzate detoxified by ethyl acetate extraction,yeast adsorption and sodium sulfite treatment. The sugar utilization ratio and ethanol yield of the ASC pre-hydrolyzate after detoxification by ethyl acetate extraction were 95. 40 % and 90. 71 %,respectively,after 36 h. The sugar utilization ratio and ethanol yield of the ASC pre-hydrolyzate after detoxification by yeast adsorption were 97. 83 % and 81. 98 %,respectively,after 48 h. The sugar utilization ratio and ethanol yield of the ASC pre-hydrolyzate after detoxification by sodium sulfite treatment were 95. 55 % and84. 74 %,respectively,after 48 h. Although the detoxification effect of ethyl acetate extraction exhibited the best performance,yeast adsorption and sodium sulfite treatment were the most potential option from the point of industrial application perspective.