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High-solids hydrolysis of corn stover to achieve high sugar yield and concentration through high xylan recovery from magnesium oxide-ethanol pretreatment
- Li, Jun, Zhang, Meng, Wang, Donghai
- Bioresource technology 2019 v.280 pp. 352-359
- biomass, cellulose, corn stover, enzymatic hydrolysis, ethanol, hydrolysis, lignin, magnesium, magnesium oxide, mixing, polysorbates, sugars, xylan
- MgO-ethanol pretreatment was studied to boost sugar conversions and concentrations during enzymatic hydrolysis. Although corn stover pretreated by MgO and 50% ethanol had the highest glucan and xylan recoveries (89 and 71%), excessive xylan/glucan ratio (54.8%) hinders the access of enzyme to internal cellulose and hemicellulose and only 57% glucan and 46% xylan conversions and 43 g/L sugars were obtained after hydrolysis (10%-solids loading and 2 mL enzyme/g treated biomass). Corn stover pretreated by MgO and 30% ethanol had a moderate xylan/glucan ratio (39.1%), achieving higher glucan and xylan conversions (58 and 48%) and sugar concentrations (70 g/L) after hydrolysis (16%-solids loading and 1 mL enzyme/g treated biomass). A 16%-solids loading largely avoids the poor mixing issue caused by excessive high-solids loading. The addition of Tween 80 effectively eased the binding of lignin with enzyme, boosting glucan and xylan conversions to 67 and 68% and sugar concentrations to 89 g/L.