Aqua-ammonia pretreatment of corn stover for enhancing enzymatic saccharification

Aqua-ammonia pretreatment of corn stover was provided in a 1.2 L high pressure reactor with two ammonia:biomass ratios of 1:1(w/w)and 2:1(w/w);at three temperatures:60℃,90℃and 120℃,and two treatment time:5 min and 30 min.Pretreatment with water was used as control.The pretreated samples were saccharified to fermentable sugars by commercial enzymes ACCELERASE 1500(cellulase)and ACCELERASE XC(xylanases).For ammonia:biomass ratio of 1:1,the yield of total fermentable sugar was 87%at 90℃for 30 min treatment.In case of ammonia:biomass ratio of 2:1,fermentable sugar yield increased four fold of that of control.Maximum fermentable sugar yield of 99%was obtained for 2:1 ammonia:biomass ratio,90℃,and 30 min treatment time.The results of this study are very promising for improving fermentable sugar yield from corn stover using smaller amount of ammonia than the ammonia fiber explosion and other pretreatments such as strong acid or alkali pretreatments.However,further optimization is required for reducing pretreatment time.