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Effect of Pretreatment Severity on Accumulation of Major Degradation Products from Dilute Acid Pretreated Corn Stover and Subsequent Inhibition of Enzymatic Hydrolysis of Cellulose
- Um, Byung-Hwan, van Walsum, G. Peter
- Applied biochemistry and biotechnology 2012 v.168 no.2 pp. 406-420
- acetic acid, cellulose, corn stover, enzymatic hydrolysis, formic acid, furfural, hydrolysis, hydroxymethylfurfural, industry, lactic acid, oligosaccharides, paper pulp, temperature, xylose
- The concept of reaction severity, which combines residence time and temperature, is often used in the pulp and paper and biorefining industries. The influence of corn stover pretreatment severity on yield of sugar and major degradation products and subsequent effects on enzymatic cellulose hydrolysis was investigated. The pretreatment residence time and temperature, combined into the severity factor (Log R o), were varied with constant acid concentration. With increasing severity, increasing concentrations of furfural and 5-hydroxymethylfurfural (5-HMF) coincided with decreasing yields of oligosaccharides. With further increase in severity factor, the concentrations of furans decreased, while the formation of formic acid and lactic acid increased. For example, from severity 3.87 to 4.32, xylose decreased from 6.39 to 5.26Â mg/mL, while furfural increased from 1.04 to 1.33Â mg/mL; as the severity was further increased to 4.42, furfural diminished to 1.23Â mg/mL as formate rose from 0.62 to 1.83Â mg/mL. The effects of dilute acid hydrolyzate, acetic acid, and lignin, in particular, on enzymatic hydrolysis were investigated with a rapid microassay method. The microplate method gave considerable time and cost savings compared to the traditional assay protocol, and it is applicable to a broad range of lignocellulosic substrates.