Pretreatment of Lignocellulosic Biomass with Recycled Black Liquor for Sugar Production

摘要

Corn stover is a promising cellulosic feedstock for bioethanol production, which showed a higher susceptibility to alkaline pretreatment than switchgrass in our preliminary experiments. To improve the cost-effectiveness of corn stover-based bioethanolproduction, the spent alkaline liquid (black liquor) from sodium hydroxide (NaOH) pretreatment of switchgrass at previously determined best conditions (2% NaOH (w/v), 6h, 21 °C) was collected and used for the pretreatment of corn stover at room temperature. The results showed that, the sugar productions of corn stover after black liquor pretreatment were comparable with, if not higher than, those after pretreatment using 1%or 2% NaOH solution. After 24-h black liquor pretreatment, the glucose and xylose yields of corn stover during enzymatic hydrolysis reached 287.7 mg/g raw biomass and 145.3 mg/g raw biomass, respectively, which were 71.5% and 63.6% of the theoretical glucose and xylose yields, respectively. The high sugar production achieved was due to the high pH of black liquor and its considerable carbohydrate content.