Statistical optimization of dilute acid and H2O2 alkaline pretreatment using surface response methodology and tween 80 for the enhancement of the enzymatic hydrolysis of corncob

Lignocellulosic biomass is an attractive raw material for the production of bioethanol because of its abundance and cheapness, but due to its complex structure the enzymes can penetrate the substrate and obtaining the fermentable sugars from the cellulose is a slow process. As indicated above, lignocellulosic biomass has to pass pretreatments to enhance the enzymatic saccharification. Dilute acid and alkaline H2O2 pretreatments show promises to cheapen the process, making the scaling to industrial stage possible. The optimum conditions for the dilute acid pretreatment were time, 33 min, and acid concentration of 1.56% v/v, obtaining a xylose yield of 89.9% and removing 83.2% of hemicellulose. The alkaline H2O2 pretreatment obtained a glucose concentration of 62.4 g/L with 5% H2O2, liquid:solid ratio 13.47:1 and time 20.7 h. Tween 80 increased the global glucose yield at 87% with 0.3% w/v of Tween and 5-h contact time. The dilute acid pretreatment removed 83% of the hemicellulose in corncob and the alkaline H2O2 pretreatment 56.8% of lignin, obtaining 71% of glucose yield. Finally, Tween 80 increased 19% of global glucose yield.