Intensification of bioethanol production by using Tween 80 to enhance dilute acid pretreatment and enzymatic saccharification of corncob

In second-generation bioethanol production, pretreatment and saccharification have been considered one of the most expensive steps. Thus, we present an approach to improve bioethanol yield by using surfactant con-comitantly with corncob pretreatment and saccharification. A response surface methodology (RSM) evaluated the Tween 80 (0%, 5.0%, and 10.0% w/w), in both corncob pretreatment and saccharification, and the enzyme dosage (CellicCTec2: 5.0, 17.5, and 30.0 FPU/g(dry matter)) on enzymatic digestibility of the acid pretreated biomass. According to the results, higher glucose yields (similar to 80-85%) could be obtained by reducing the highest enzyme dosage to 41.67% concomitantly by reducing the Tween 80 to 34.2% or 63% by adding it (10% w/w) into only the pretreatment or saccharification, respectively. The RSM suggested applying enzyme dosage between 17.5 and 25.5 FPU/gg(dry matter) associated with the highest Tween 80 amount to improve glucose yield. For statistical validation model, the maximum glucose (80.54%) and xylose (70.66%) yields were obtained for 10.0% of surfactant in both pretreatment and saccharification (25.50 FPU/gg(dry matter)). The hydrolysate was supplemented and fermented by Scheffersomyces stipitis CBS 6054. This yeast fermented the sugars glucose (98.95%), xylose (64.90%), and cellobiose (60.12%) efficiently into ethanol with high yield (0.37 g/g) and volumetric productivity (1.02 g(ethanol)/L.h).