Green liquor pretreatment for improving enzymatic hydrolysis of corn stover

► Pretreated solids show significant delignification at a high sulfidity level. ► Sugar yield of corn stover is greatly improved after green liquor pretreatment. ► 70% of the original polysaccharides can be converted into fermentable sugars. ► Green liquor (Na2CO3 + Na2S) is cheap and readily available in any kraft mill. ► The method can be used to repurpose a kraft pulp mill for bioethanol production.