Effect of stover fraction on glucose production using enzymatic hydrolysis

Corn stover was fractionated into three fractions: cobs, stalks, and leaves and husks. The fractions were dried and ground through a 2 mm screen. Samples of the three fractions and whole corn stover with and without NaOH pretreatment were subjected to enzymatic hydrolysis in order to determine the effect of fractionation on glucose production. The average amounts of glucose released after 60 h of hydrolysis from pretreated cobs, leaves and husks, stalks, and whole stover were 0.50, 0.36, 0.28, and 0.36 g/g dry biomass, respectively. The average amounts of glucose released after 60 h of hydrolysis from nonpretreated cobs, leaves and husks, stalks, and whole stover were 0.32, 0.23, 0.17, and 0.20 g/g dry biomass, respectively. Pretreatment resulted in an average increase of 60% in glucose production for all fractions and whole stover. The effect of stover fraction type on glucose production was significant with and without pretreatment. By collecting the fractions of the corn stover with the highest glucose potential (all the cobs and 74% of the leaves and husks) and leaving the remaining fraction (26% of the leaves and husks, and all the stalks) in the field for erosion control, the glucose potential of the collected biomass would increase by 21%. This could represent a decrease of up to 17% in the cost of ethanol production. This indicates that fractionation and collection of the biomass with the highest glucose potential may produce a higher quality feedstock for glucose production.