2-03: Improved xylan hydrolysis through deacetylation and high solids dilute acid pretreatment of corn stover

Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from biomass.  However, this process requires severe conditions to overcome the recalcitrance of biomass and improve glucose and xylose yield. Evidence has shown that xylan units are linked to lignin via covalent bonds, such as lignin carbohydrate complex (LCC) between acetyl groups and lignin, which is thought to be responsible for slow dissolution of xylan during the final stages of acid pretreatment and enzymatic hydrolysis. Liberated acetic acid also depresses ethanol yield during fermentation. Successful removal of acetyl groups from native corn stover by alkaline de-esterification could potentially increase monomeric xylose yields from pretreatment and enzymatic hydrolysis, improve cellulose digestibility, and reduce the toxicity of the fermentation broth.  Results show that deacetylation improves xylan and glucan hydrolysis in high solids dilute acid pretreatment, as well as low solids and whole slurry enzymatic hydrolysis when compared to dilute acid pretreated controls.