Evaluation of ethanol production from corncob using Scheffersomyces (Pichia) stipitis CBS 6054 by volumetric scale-up.

In scale-up, the potential of ethanol production by dilute sulfuric acid pretreatment using corncob was investigated. Pretreatments were performed at 170 °C with various acid concentrations ranging from 0% to 1.656% based on oven dry weight. Following pretreatment, pretreated biomass yield ranged from 59% to 67%. More than 90% of xylan was removed at 0.828% of sulfuric acid. At same pretreatment condition, the highest glucose yield obtained from pretreated biomass by enzymatic hydrolysis was about 76%, based on a glucan content of 37/100 g. In hydrolysate obtained by pretreatment, glucose concentration was low, while xylose concentration was significantly increased above 0.368% of sulfuric acid. At 1.656% of sulfuric acid, xylose and glucose concentration was highest. In subsequent, fermentation with hydrolysate, maximal ethanol yield was attained after 24 h with 0.368% of sulfuric acid. The fermentation efficiency of hydrolysate obtained by enzymatic hydrolysis reached a maximum of 75% at an acid charge of 0.368%.